diff --git a/core/aux_config.mk b/core/aux_config.mk
new file mode 100644
index 0000000..decff34
--- /dev/null
+++ b/core/aux_config.mk
@@ -0,0 +1,183 @@
+variant_list := $(filter AUX-%,$(MAKECMDGOALS))
+
+ifdef variant_list
+AUX_OS_VARIANT_LIST := $(patsubst AUX-%,%,$(variant_list))
+else
+AUX_OS_VARIANT_LIST := $(TARGET_AUX_OS_VARIANT_LIST)
+endif
+
+# exclude AUX targets from build
+ifeq ($(AUX_OS_VARIANT_LIST),none)
+AUX_OS_VARIANT_LIST :=
+endif
+
+# temporary workaround to support external toolchain
+ifeq ($(NANOHUB_TOOLCHAIN),)
+AUX_OS_VARIANT_LIST :=
+endif
+
+# setup toolchain paths for various CPU architectures
+# this one will come from android prebuilts eventually
+AUX_TOOLCHAIN_cortexm4 := $(NANOHUB_TOOLCHAIN)
+ifeq ($(wildcard $(AUX_TOOLCHAIN_cortexm4)gcc),)
+AUX_TOOLCHAIN_cortexm4:=
+endif
+
+# there is no MAKE var that defines path to HOST toolchain
+# all the interesting paths are hardcoded in soong, and are not available from here
+# There is no other way but to hardcode them again, as we may need host x86 toolcain for AUX
+ifeq ($(HOST_OS),linux)
+AUX_TOOLCHAIN_x86 := prebuilts/gcc/linux-x86/host/x86_64-linux-glibc2.15-4.8/bin/x86_64-linux-
+endif
+
+# setup AUX globals
+AUX_SHLIB_SUFFIX := .so
+AUX_GLOBAL_ARFLAGS := crsPD
+AUX_STATIC_LIB_SUFFIX := .a
+
+# Load ever-lasting "indexed" version of AUX variant environment; it is treated as READ-ONLY from this
+# moment on.
+#
+# $(1) - variant
+# no return value
+define aux-variant-setup-paths
+$(eval AUX_OUT_ROOT_$(1) := $(PRODUCT_OUT)/aux/$(1)) \
+$(eval AUX_COMMON_OUT_ROOT_$(1) := $(AUX_OUT_ROOT_$(1))/common) \
+$(eval AUX_OUT_$(1) := $(AUX_OUT_ROOT_$(1))/$(AUX_OS_$(1))-$(AUX_ARCH_$(1))-$(AUX_CPU_$(1))) \
+$(eval AUX_OUT_INTERMEDIATES_$(1) := $(AUX_OUT_$(1))/obj) \
+$(eval AUX_OUT_COMMON_INTERMEDIATES_$(1) := $(AUX_COMMON_OUT_ROOT_$(1))/obj) \
+$(eval AUX_OUT_HEADERS_$(1) := $(AUX_OUT_INTERMEDIATES_$(1))/include) \
+$(eval AUX_OUT_INTERMEDIATE_LIBRARIES_$(1) := $(AUX_OUT_INTERMEDIATES_$(1))/lib) \
+$(eval AUX_OUT_NOTICE_FILES_$(1) := $(AUX_OUT_INTERMEDIATES_$(1))/NOTICE_FILES) \
+$(eval AUX_OUT_FAKE_$(1) := $(AUX_OUT_$(1))/fake_packages) \
+$(eval AUX_OUT_GEN_$(1) := $(AUX_OUT_$(1))/gen) \
+$(eval AUX_OUT_COMMON_GEN_$(1) := $(AUX_COMMON_OUT_ROOT_$(1))/gen) \
+$(eval AUX_OUT_EXECUTABLES_$(1) := $(AUX_OUT_$(1))/bin) \
+$(eval AUX_OUT_UNSTRIPPED_$(1) := $(AUX_OUT_$(1))/symbols)
+endef
+
+# Copy "indexed" AUX environment for given VARIANT into
+# volatile not-indexed set of variables for simplicity of access.
+# Injection of index support throughout the build system is suboptimal
+# hence volatile environment is constructed
+# Unlike HOST*, TARGET* variables, AUX* variables are NOT read-only, but their
+# indexed versions are.
+#
+# $(1) - variant
+# no return value
+define aux-variant-load-env
+$(eval AUX_OS_VARIANT:=$(1)) \
+$(eval AUX_OS:=$(AUX_OS_$(1))) \
+$(eval AUX_ARCH:=$(AUX_ARCH_$(1))) \
+$(eval AUX_SUBARCH:=$(AUX_SUBARCH_$(1))) \
+$(eval AUX_CPU:=$(AUX_CPU_$(1))) \
+$(eval AUX_OS_PATH:=$(AUX_OS_PATH_$(1))) \
+$(eval AUX_OUT_ROOT := $(AUX_OUT_ROOT_$(1))) \
+$(eval AUX_COMMON_OUT_ROOT := $(AUX_COMMON_OUT_ROOT_$(1))) \
+$(eval AUX_OUT := $(AUX_OUT_$(1))) \
+$(eval AUX_OUT_INTERMEDIATES := $(AUX_OUT_INTERMEDIATES_$(1))) \
+$(eval AUX_OUT_COMMON_INTERMEDIATES := $(AUX_OUT_COMMON_INTERMEDIATES_$(1))) \
+$(eval AUX_OUT_HEADERS := $(AUX_OUT_HEADERS_$(1))) \
+$(eval AUX_OUT_INTERMEDIATE_LIBRARIES := $(AUX_OUT_INTERMEDIATE_LIBRARIES_$(1))) \
+$(eval AUX_OUT_NOTICE_FILES := $(AUX_OUT_NOTICE_FILES_$(1))) \
+$(eval AUX_OUT_FAKE := $(AUX_OUT_FAKE_$(1))) \
+$(eval AUX_OUT_GEN := $(AUX_OUT_GEN_$(1))) \
+$(eval AUX_OUT_COMMON_GEN := $(AUX_OUT_COMMON_GEN_$(1))) \
+$(eval AUX_OUT_EXECUTABLES := $(AUX_OUT_EXECUTABLES_$(1))) \
+$(eval AUX_OUT_UNSTRIPPED := $(AUX_OUT_UNSTRIPPED_$(1)))
+endef
+
+# given a variant:path pair, load the variant conviguration with aux-variant-setup-paths from file
+# this is a build system extension mechainsm, since configuration typically resides in non-build
+# project space
+#
+# $(1) - variant:path pair
+# $(2) - file suffix
+# no return value
+define aux-variant-import-from-pair
+$(eval _pair := $(subst :, ,$(1))) \
+$(eval _name:=$(word 1,$(_pair))) \
+$(eval _path:=$(word 2,$(_pair))) \
+$(eval include $(_path)/$(_name)$(2)) \
+$(eval AUX_OS_VARIANT_LIST_$(AUX_OS_$(1)):=) \
+$(call aux-variant-setup-paths,$(_name)) \
+$(eval AUX_ALL_VARIANTS += $(_name)) \
+$(eval AUX_ALL_OSES := $(filterout $(AUX_OS_$(_name)),$(AUX_ALL_OSES)) $(AUX_OS_$(_name))) \
+$(eval AUX_ALL_CPUS := $(filterout $(AUX_CPU_$(_name)),$(AUX_ALL_CPUS)) $(AUX_CPU_$(_name))) \
+$(eval AUX_ALL_ARCHS := $(filterout $(AUX_ARCH_$(_name)),$(AUX_ALL_ARCHS)) $(AUX_ARCH_$(_name))) \
+$(eval AUX_ALL_SUBARCHS := $(filterout $(AUX_SUBARCH_$(_name)),$(AUX_ALL_SUBARCHS)) $(AUX_SUBARCH_$(_name)))
+endef
+
+# Load system configuration referenced by AUX variant config;
+# this is a build extension mechanism; typically system config
+# resides in a non-build projects;
+# system config may define new rules and globally visible BUILD*
+# includes to support project-specific build steps and toolchains
+# MAintains list of valiants that reference this os config in OS "indexed" var
+# this facilitates multivariant build of the OS (or whataver it is the name of common component these variants share)
+#
+# $(1) - variant
+# no return value
+define aux-import-os-config
+$(eval _aioc_os := $(AUX_OS_$(1))) \
+$(eval AUX_OS_PATH_$(1) := $(patsubst $(_aioc_os):%,%,$(filter $(_aioc_os):%,$(AUX_ALL_OS_PATHS)))) \
+$(eval _aioc_os_cfg := $(AUX_OS_PATH_$(1))/$(_aioc_os)$(os_sfx)) \
+$(if $(wildcard $(_aioc_os_cfg)),,$(error AUX '$(_aioc_os)' OS config file [$(notdir $(_aioc_os_cfg))] required by AUX variant '$(1)' does not exist)) \
+$(if $(filter $(_aioc_os),$(_os_list)),,$(eval include $(_aioc_os_cfg))) \
+$(eval AUX_OS_VARIANT_LIST_$(_aioc_os) += $(1)) \
+$(eval _os_list += $(_aioc_os))
+endef
+
+# make sure that AUX config variables are minimally sane;
+# as a bare minimum they must contain the vars described by aux_env
+# Generate error if requirement is not met.
+#
+#$(1) - variant
+# no return value
+define aux-variant-validate
+$(eval _all:=) \
+$(eval _req:=$(addsuffix _$(1),$(aux_env))) \
+$(foreach var,$(_req),$(eval _all += $(var))) \
+$(eval _missing := $(filterout $(_all),$(_req))) \
+$(if $(_missing),$(error AUX variant $(1) must define vars: $(_missing)))
+endef
+
+AUX_ALL_VARIANTS :=
+AUX_ALL_OSES :=
+AUX_ALL_CPUS :=
+AUX_ALL_ARCHS :=
+AUX_ALL_SUBARCHS :=
+
+variant_sfx :=_aux_variant_config.mk
+os_sfx :=_aux_os_config.mk
+
+all_configs := $(shell find device vendor -maxdepth 4 -name '*$(variant_sfx)' -o -name '*$(os_sfx)' | sort)
+all_os_configs := $(filter %$(os_sfx),$(all_configs))
+all_variant_configs := $(filter %$(variant_sfx),$(all_configs))
+
+AUX_ALL_OS_PATHS := $(foreach f,$(all_os_configs),$(patsubst %$(os_sfx),%,$(notdir $(f))):$(patsubst %/,%,$(dir $(f))))
+AUX_ALL_OS_VARIANT_PATHS := $(foreach f,$(all_variant_configs),$(patsubst %$(variant_sfx),%,$(notdir $(f))):$(patsubst %/,%,$(dir $(f))))
+
+my_variant_pairs := $(foreach v,$(AUX_OS_VARIANT_LIST),$(filter $(v):%,$(AUX_ALL_OS_VARIANT_PATHS)))
+my_missing_variants := $(foreach v,$(AUX_OS_VARIANT_LIST),$(if $(filter $(v):%,$(AUX_ALL_OS_VARIANT_PATHS)),,$(v)))
+
+ifneq ($(strip $(my_missing_variants)),)
+$(error Don't know how to build variant(s): $(my_missing_variants))
+endif
+
+# mandatory variables
+aux_env := AUX_OS AUX_ARCH AUX_SUBARCH AUX_CPU
+
+$(foreach v,$(my_variant_pairs),$(if $(filter $(v),$(AUX_ALL_VARIANTS)),,$(call aux-variant-import-from-pair,$(v),$(variant_sfx))))
+
+ifdef AUX_ALL_VARIANTS
+_os_list :=
+$(foreach v,$(AUX_ALL_VARIANTS),\
+  $(call aux-import-os-config,$(v)) \
+  $(call aux-variant-validate,$(v)) \
+)
+endif
+
+INSTALLED_AUX_TARGETS :=
+
+droidcore: auxiliary
diff --git a/core/aux_executable.mk b/core/aux_executable.mk
new file mode 100644
index 0000000..daf30e7
--- /dev/null
+++ b/core/aux_executable.mk
@@ -0,0 +1,96 @@
+# caller might have included aux_toolchain, e.g. if custom build steps are defined
+ifeq ($(LOCAL_IS_AUX_MODULE),)
+include $(BUILD_SYSTEM)/aux_toolchain.mk
+endif
+
+ifeq ($(AUX_BUILD_NOT_COMPATIBLE),)
+
+###########################################################
+## Standard rules for building an executable file.
+##
+## Additional inputs from base_rules.make:
+## None.
+###########################################################
+
+ifeq ($(strip $(LOCAL_MODULE_CLASS)),)
+LOCAL_MODULE_CLASS := EXECUTABLES
+endif
+
+$(call $(aux-executable-hook))
+
+###########################################################
+## Standard rules for building any target-side binaries
+## with dynamic linkage (dynamic libraries or executables
+## that link with dynamic libraries)
+##
+## Files including this file must define a rule to build
+## the target $(linked_module).
+###########################################################
+
+# The name of the target file, without any path prepended.
+# This duplicates logic from base_rules.mk because we need to
+# know its results before base_rules.mk is included.
+include $(BUILD_SYSTEM)/configure_module_stem.mk
+
+intermediates := $(call local-intermediates-dir)
+
+# Define the target that is the unmodified output of the linker.
+# The basename of this target must be the same as the final output
+# binary name, because it's used to set the "soname" in the binary.
+# The includer of this file will define a rule to build this target.
+linked_module := $(intermediates)/LINKED/$(my_built_module_stem)
+
+ALL_ORIGINAL_DYNAMIC_BINARIES += $(linked_module)
+
+# Because AUX_SYMBOL_FILTER_FILE depends on ALL_ORIGINAL_DYNAMIC_BINARIES,
+# the linked_module rules won't necessarily inherit the PRIVATE_
+# variables from LOCAL_BUILT_MODULE.  This tells binary.make to explicitly
+# define the PRIVATE_ variables for linked_module as well as for
+# LOCAL_BUILT_MODULE.
+LOCAL_INTERMEDIATE_TARGETS += $(linked_module)
+
+###################################
+include $(BUILD_SYSTEM)/binary.mk
+###################################
+
+aux_output := $(linked_module)
+
+ifneq ($(LOCAL_CUSTOM_BUILD_STEP_INPUT),)
+ifneq ($(LOCAL_CUSTOM_BUILD_STEP_OUTPUT),)
+
+# injecting custom build steps
+$(LOCAL_CUSTOM_BUILD_STEP_INPUT): $(aux_output)
+	@echo "$(AUX_DISPLAY) custom copy: $(PRIVATE_MODULE) ($@)"
+	@mkdir -p $(dir $@)
+	$(hide) $(copy-file-to-target)
+
+aux_output := $(LOCAL_CUSTOM_BUILD_STEP_OUTPUT)
+
+endif
+endif
+
+$(LOCAL_BUILT_MODULE): $(aux_output)
+	@echo "$(AUX_DISPLAY) final copy: $(PRIVATE_MODULE) ($@)"
+	@mkdir -p $(dir $@)
+	$(hide) $(copy-file-to-target)
+
+INSTALLED_AUX_TARGETS += $(LOCAL_INSTALLED_MODULE)
+
+$(cleantarget): PRIVATE_CLEAN_FILES += \
+    $(linked_module) \
+
+# Define PRIVATE_ variables from global vars
+$(linked_module): PRIVATE_TARGET_OUT_INTERMEDIATE_LIBRARIES := $(AUX_OUT_INTERMEDIATE_LIBRARIES)
+$(linked_module): PRIVATE_POST_LINK_CMD := $(LOCAL_POST_LINK_CMD)
+
+ifeq ($(LOCAL_FORCE_STATIC_EXECUTABLE),true)
+$(linked_module): $(all_objects) $(all_libraries) $(LOCAL_ADDITIONAL_DEPENDENCIES)
+	$(transform-o-to-aux-static-executable)
+	$(PRIVATE_POST_LINK_CMD)
+else
+$(linked_module): $(all_objects) $(all_libraries) $(LOCAL_ADDITIONAL_DEPENDENCIES)
+	$(transform-o-to-aux-executable)
+	$(PRIVATE_POST_LINK_CMD)
+endif
+
+endif # AUX_BUILD_NOT_COMPATIBLE
diff --git a/core/aux_static_library.mk b/core/aux_static_library.mk
new file mode 100644
index 0000000..d88478d
--- /dev/null
+++ b/core/aux_static_library.mk
@@ -0,0 +1,27 @@
+ifeq ($(LOCAL_IS_AUX_MODULE),)
+include $(BUILD_SYSTEM)/aux_toolchain.mk
+endif
+
+ifeq ($(AUX_BUILD_NOT_COMPATIBLE),)
+
+ifeq ($(strip $(LOCAL_MODULE_CLASS)),)
+LOCAL_MODULE_CLASS := STATIC_LIBRARIES
+endif
+ifeq ($(strip $(LOCAL_MODULE_SUFFIX)),)
+LOCAL_MODULE_SUFFIX := .a
+endif
+
+LOCAL_UNINSTALLABLE_MODULE := true
+
+ifneq ($(strip $(LOCAL_MODULE_STEM)$(LOCAL_BUILT_MODULE_STEM)),)
+$(error $(LOCAL_PATH): Cannot set module stem for a library)
+endif
+
+include $(BUILD_SYSTEM)/binary.mk
+
+$(LOCAL_BUILT_MODULE) : PRIVATE_AR := $(AUX_AR)
+$(LOCAL_BUILT_MODULE) : $(built_whole_libraries)
+$(LOCAL_BUILT_MODULE) : $(all_objects)
+	$(transform-o-to-aux-static-lib)
+
+endif # AUX_BUILD_NOT_COMPATIBLE
diff --git a/core/aux_toolchain.mk b/core/aux_toolchain.mk
new file mode 100644
index 0000000..de0b139
--- /dev/null
+++ b/core/aux_toolchain.mk
@@ -0,0 +1,53 @@
+###########################################################
+# takes form LOCAL_AUX_TOOLCHAIN_$(LOCAL_AUX_CPU)
+###########################################################
+
+###############################
+# setup AUX environment
+###############################
+
+# shortcuts for targets with a single instance of OS, ARCH, VARIANT, CPU
+AUX_TOOLCHAIN := $(if $(LOCAL_AUX_TOOLCHAIN),$(LOCAL_AUX_TOOLCHAIN),$(AUX_TOOLCHAIN_$(AUX_CPU)))
+AUX_BUILD_NOT_COMPATIBLE:=
+ifeq ($(strip $(AUX_TOOLCHAIN)),)
+  ifeq ($(strip $(AUX_CPU)),)
+    $(warning $(LOCAL_PATH): $(LOCAL_MODULE): Undefined CPU for AUX toolchain)
+    AUX_BUILD_NOT_COMPATIBLE += TOOLCHAIN
+  else
+    $(warning $(LOCAL_PATH): $(LOCAL_MODULE): Undefined AUX toolchain for CPU=$(AUX_CPU))
+    AUX_BUILD_NOT_COMPATIBLE += TOOLCHAIN
+  endif
+endif
+
+AUX_BUILD_NOT_COMPATIBLE += $(foreach var,OS ARCH SUBARCH CPU OS_VARIANT,$(if $(LOCAL_AUX_$(var)),$(if \
+    $(filter $(LOCAL_AUX_$(var)),$(AUX_$(var))),,$(var))))
+
+AUX_BUILD_NOT_COMPATIBLE := $(strip $(AUX_BUILD_NOT_COMPATIBLE))
+
+ifneq ($(AUX_BUILD_NOT_COMPATIBLE),)
+$(info $(LOCAL_PATH): $(LOCAL_MODULE): not compatible: "$(AUX_BUILD_NOT_COMPATIBLE)" with)
+$(info ====> OS=$(AUX_OS) CPU=$(AUX_CPU) ARCH=$(AUX_ARCH) SUBARCH=$(AUX_SUBARCH) OS_VARIANT=$(AUX_OS_VARIANT))
+$(info ====> TOOLCHAIN=$(AUX_TOOLCHAIN))
+endif
+
+AUX_AR := $(AUX_TOOLCHAIN)ar
+AUX_AS := $(AUX_TOOLCHAIN)gcc
+AUX_CC := $(AUX_TOOLCHAIN)gcc
+AUX_CXX := $(AUX_TOOLCHAIN)g++
+AUX_LINKER := $(AUX_TOOLCHAIN)ld
+AUX_OBJCOPY := $(AUX_TOOLCHAIN)objcopy
+AUX_OBJDUMP := $(AUX_TOOLCHAIN)objdump
+
+###############################
+# setup Android environment
+###############################
+
+LOCAL_IS_AUX_MODULE := true
+LOCAL_2ND_ARCH_VAR_PREFIX :=
+LOCAL_CC := $(AUX_CC)
+LOCAL_CXX := $(AUX_CXX)
+LOCAL_NO_DEFAULT_COMPILER_FLAGS := true
+LOCAL_SYSTEM_SHARED_LIBRARIES :=
+LOCAL_CXX_STL := none
+LOCAL_NO_PIC := true
+LOCAL_NO_LIBCOMPILER_RT := true
diff --git a/core/base_rules.mk b/core/base_rules.mk
index 1daf229..aac551a 100644
--- a/core/base_rules.mk
+++ b/core/base_rules.mk
@@ -33,6 +33,7 @@
 endif
 
 LOCAL_IS_HOST_MODULE := $(strip $(LOCAL_IS_HOST_MODULE))
+LOCAL_IS_AUX_MODULE := $(strip $(LOCAL_IS_AUX_MODULE))
 ifdef LOCAL_IS_HOST_MODULE
   ifneq ($(LOCAL_IS_HOST_MODULE),true)
     $(error $(LOCAL_PATH): LOCAL_IS_HOST_MODULE must be "true" or empty, not "$(LOCAL_IS_HOST_MODULE)")
@@ -43,8 +44,18 @@
     my_prefix := $(LOCAL_HOST_PREFIX)
   endif
   my_host := host-
+  my_kind := HOST
 else
-  my_prefix := TARGET_
+  ifdef LOCAL_IS_AUX_MODULE
+    ifneq ($(LOCAL_IS_AUX_MODULE),true)
+      $(error $(LOCAL_PATH): LOCAL_IS_AUX_MODULE must be "true" or empty, not "$(LOCAL_IS_AUX_MODULE)")
+    endif
+    my_prefix := AUX_
+    my_kind := AUX
+  else
+    my_prefix := TARGET_
+    my_kind :=
+  endif
   my_host :=
 endif
 
@@ -195,9 +206,13 @@
 my_register_name := $(my_register_name)$($(my_prefix)2ND_ARCH_MODULE_SUFFIX)
 endif
 endif
+
+# variant is enough to make nano class unique; it serves as a key to lookup (OS,ARCH) tuple
+aux_class := $($(my_prefix)OS_VARIANT)
 # Make sure that this IS_HOST/CLASS/MODULE combination is unique.
 module_id := MODULE.$(if \
-    $(LOCAL_IS_HOST_MODULE),$($(my_prefix)OS),TARGET).$(LOCAL_MODULE_CLASS).$(my_register_name)
+    $(LOCAL_IS_HOST_MODULE),$($(my_prefix)OS),$(if \
+    $(LOCAL_IS_AUX_MODULE),$(aux_class),TARGET)).$(LOCAL_MODULE_CLASS).$(my_register_name)
 ifdef $(module_id)
 $(error $(LOCAL_PATH): $(module_id) already defined by $($(module_id)))
 endif
@@ -292,6 +307,7 @@
 ###########################################################
 $(LOCAL_INTERMEDIATE_TARGETS) : PRIVATE_PATH:=$(LOCAL_PATH)
 $(LOCAL_INTERMEDIATE_TARGETS) : PRIVATE_IS_HOST_MODULE := $(LOCAL_IS_HOST_MODULE)
+$(LOCAL_INTERMEDIATE_TARGETS) : PRIVATE_IS_AUX_MODULE := $(LOCAL_IS_AUX_MODULE)
 $(LOCAL_INTERMEDIATE_TARGETS) : PRIVATE_HOST:= $(my_host)
 $(LOCAL_INTERMEDIATE_TARGETS) : PRIVATE_PREFIX := $(my_prefix)
 
diff --git a/core/binary.mk b/core/binary.mk
index 10d447b..9181699 100644
--- a/core/binary.mk
+++ b/core/binary.mk
@@ -220,6 +220,7 @@
 # MinGW spits out warnings about -fPIC even for -fpie?!) being ignored because
 # all code is position independent, and then those warnings get promoted to
 # errors.
+ifneq ($(LOCAL_NO_PIC),true)
 ifneq ($($(my_prefix)OS),windows)
 ifneq ($(filter EXECUTABLES NATIVE_TESTS,$(LOCAL_MODULE_CLASS)),)
 my_cflags += -fpie
@@ -227,6 +228,7 @@
 my_cflags += -fPIC
 endif
 endif
+endif
 
 ifdef LOCAL_IS_HOST_MODULE
 my_src_files += $(LOCAL_SRC_FILES_$($(my_prefix)OS)) $(LOCAL_SRC_FILES_$($(my_prefix)OS)_$($(my_prefix)$(LOCAL_2ND_ARCH_VAR_PREFIX)ARCH))
@@ -265,6 +267,13 @@
 ifdef LOCAL_CLANG_$($(my_prefix)$(LOCAL_2ND_ARCH_VAR_PREFIX)ARCH)
 my_clang := $(strip $(LOCAL_CLANG_$($(my_prefix)$(LOCAL_2ND_ARCH_VAR_PREFIX)ARCH)))
 endif
+
+# if custom toolchain is in use, default is not to use clang, if not explicitly required
+ifneq ($(my_cc)$(my_cxx),)
+    ifeq ($(my_clang),)
+        my_clang := false
+    endif
+endif
 # Issue warning if LOCAL_CLANG* is set to false and the local makefile is not found
 # in the exception project list.
 ifeq ($(my_clang),false)
@@ -336,15 +345,17 @@
 ifneq ($(strip $(CUSTOM_$(my_prefix)$(LOCAL_2ND_ARCH_VAR_PREFIX)LINKER)),)
   my_linker := $(CUSTOM_$(my_prefix)$(LOCAL_2ND_ARCH_VAR_PREFIX)LINKER)
 else
-  my_linker := $($(LOCAL_2ND_ARCH_VAR_PREFIX)TARGET_LINKER)
+  my_linker := $($(LOCAL_2ND_ARCH_VAR_PREFIX)$(my_prefix)LINKER)
 endif
 
 include $(BUILD_SYSTEM)/config_sanitizers.mk
 
+ifneq ($(LOCAL_NO_LIBCOMPILER_RT),true)
 # Add in libcompiler_rt for all regular device builds
 ifeq (,$(LOCAL_SDK_VERSION)$(WITHOUT_LIBCOMPILER_RT))
   my_static_libraries += $(COMPILER_RT_CONFIG_EXTRA_STATIC_LIBRARIES)
 endif
+endif
 
 ####################################################
 ## Add FDO flags if FDO is turned on and supported
@@ -384,24 +395,24 @@
 my_target_global_cppflags := $(my_ndk_stl_cppflags)
 else
 my_target_global_c_includes := $(SRC_HEADERS) \
-    $($(LOCAL_2ND_ARCH_VAR_PREFIX)TARGET_PROJECT_INCLUDES) \
-    $($(LOCAL_2ND_ARCH_VAR_PREFIX)TARGET_C_INCLUDES)
+    $($(LOCAL_2ND_ARCH_VAR_PREFIX)$(my_prefix)PROJECT_INCLUDES) \
+    $($(LOCAL_2ND_ARCH_VAR_PREFIX)$(my_prefix)C_INCLUDES)
 my_target_global_c_system_includes := $(SRC_SYSTEM_HEADERS) \
-    $($(LOCAL_2ND_ARCH_VAR_PREFIX)TARGET_PROJECT_SYSTEM_INCLUDES) \
-    $($(LOCAL_2ND_ARCH_VAR_PREFIX)TARGET_C_SYSTEM_INCLUDES)
+    $($(LOCAL_2ND_ARCH_VAR_PREFIX)$(my_prefix)PROJECT_SYSTEM_INCLUDES) \
+    $($(LOCAL_2ND_ARCH_VAR_PREFIX)$(my_prefix)C_SYSTEM_INCLUDES)
 my_target_global_cppflags :=
 endif # LOCAL_SDK_VERSION
 
 ifeq ($(my_clang),true)
-my_target_global_cflags := $($(LOCAL_2ND_ARCH_VAR_PREFIX)CLANG_TARGET_GLOBAL_CFLAGS)
-my_target_global_conlyflags := $($(LOCAL_2ND_ARCH_VAR_PREFIX)CLANG_TARGET_GLOBAL_CONLYFLAGS)
-my_target_global_cppflags += $($(LOCAL_2ND_ARCH_VAR_PREFIX)CLANG_TARGET_GLOBAL_CPPFLAGS)
-my_target_global_ldflags := $($(LOCAL_2ND_ARCH_VAR_PREFIX)CLANG_TARGET_GLOBAL_LDFLAGS)
+my_target_global_cflags := $($(LOCAL_2ND_ARCH_VAR_PREFIX)CLANG_$(my_prefix)GLOBAL_CFLAGS)
+my_target_global_conlyflags := $($(LOCAL_2ND_ARCH_VAR_PREFIX)CLANG_$(my_prefix)GLOBAL_CONLYFLAGS)
+my_target_global_cppflags += $($(LOCAL_2ND_ARCH_VAR_PREFIX)CLANG_$(my_prefix)GLOBAL_CPPFLAGS)
+my_target_global_ldflags := $($(LOCAL_2ND_ARCH_VAR_PREFIX)CLANG_$(my_prefix)GLOBAL_LDFLAGS)
 else
-my_target_global_cflags := $($(LOCAL_2ND_ARCH_VAR_PREFIX)TARGET_GLOBAL_CFLAGS)
-my_target_global_conlyflags := $($(LOCAL_2ND_ARCH_VAR_PREFIX)TARGET_GLOBAL_CONLYFLAGS)
-my_target_global_cppflags += $($(LOCAL_2ND_ARCH_VAR_PREFIX)TARGET_GLOBAL_CPPFLAGS)
-my_target_global_ldflags := $($(LOCAL_2ND_ARCH_VAR_PREFIX)TARGET_GLOBAL_LDFLAGS)
+my_target_global_cflags := $($(LOCAL_2ND_ARCH_VAR_PREFIX)$(my_prefix)GLOBAL_CFLAGS)
+my_target_global_conlyflags := $($(LOCAL_2ND_ARCH_VAR_PREFIX)$(my_prefix)GLOBAL_CONLYFLAGS)
+my_target_global_cppflags += $($(LOCAL_2ND_ARCH_VAR_PREFIX)$(my_prefix)GLOBAL_CPPFLAGS)
+my_target_global_ldflags := $($(LOCAL_2ND_ARCH_VAR_PREFIX)$(my_prefix)GLOBAL_LDFLAGS)
 endif # my_clang
 
 $(LOCAL_INTERMEDIATE_TARGETS): PRIVATE_GLOBAL_C_INCLUDES := $(my_target_global_c_includes)
@@ -460,9 +471,9 @@
 endif
 
 ifeq ($(my_clang),true)
-    my_coverage_lib := $($(LOCAL_2ND_ARCH_VAR_PREFIX)TARGET_LIBPROFILE_RT)
+    my_coverage_lib := $($(LOCAL_2ND_ARCH_VAR_PREFIX)$(my_prefix)LIBPROFILE_RT)
 else
-    my_coverage_lib := $(call intermediates-dir-for,STATIC_LIBRARIES,libgcov,,,$(LOCAL_2ND_ARCH_VAR_PREFIX))/libgcov.a
+    my_coverage_lib := $(call intermediates-dir-for,STATIC_LIBRARIES,libgcov,$(filter AUX,$(my_kind)),,$(LOCAL_2ND_ARCH_VAR_PREFIX))/libgcov.a
 endif
 
 $(LOCAL_INTERMEDIATE_TARGETS): PRIVATE_TARGET_COVERAGE_LIB := $(my_coverage_lib)
@@ -490,7 +501,7 @@
 ifneq ($(strip $(LOCAL_IS_HOST_MODULE)),)
   my_syntax_arch := host
 else
-  my_syntax_arch := $(TARGET_$(LOCAL_2ND_ARCH_VAR_PREFIX)ARCH)
+  my_syntax_arch := $($(my_prefix)$(LOCAL_2ND_ARCH_VAR_PREFIX)ARCH)
 endif
 
 ifeq ($(strip $(my_cc)),)
@@ -1245,9 +1256,9 @@
 import_includes := $(intermediates)/import_includes
 import_includes_deps := $(strip \
     $(foreach l, $(installed_shared_library_module_names), \
-      $(call intermediates-dir-for,SHARED_LIBRARIES,$(l),$(LOCAL_IS_HOST_MODULE),,$(LOCAL_2ND_ARCH_VAR_PREFIX),$(my_host_cross))/export_includes) \
+      $(call intermediates-dir-for,SHARED_LIBRARIES,$(l),$(my_kind),,$(LOCAL_2ND_ARCH_VAR_PREFIX),$(my_host_cross))/export_includes) \
     $(foreach l, $(my_static_libraries) $(my_whole_static_libraries), \
-      $(call intermediates-dir-for,STATIC_LIBRARIES,$(l),$(LOCAL_IS_HOST_MODULE),,$(LOCAL_2ND_ARCH_VAR_PREFIX),$(my_host_cross))/export_includes))
+      $(call intermediates-dir-for,STATIC_LIBRARIES,$(l),$(my_kind),,$(LOCAL_2ND_ARCH_VAR_PREFIX),$(my_host_cross))/export_includes))
 $(import_includes): PRIVATE_IMPORT_EXPORT_INCLUDES := $(import_includes_deps)
 $(import_includes) : $(import_includes_deps)
 	@echo Import includes file: $@
@@ -1260,7 +1271,6 @@
 	$(hide) touch $@
 endif
 
-
 ####################################################
 ## Verify that NDK-built libraries only link against
 ## other NDK-built libraries
@@ -1276,11 +1286,11 @@
 endif
 my_link_type_deps := $(strip \
    $(foreach l,$(my_whole_static_libraries) $(my_static_libraries), \
-     $(call intermediates-dir-for,STATIC_LIBRARIES,$(l),$(LOCAL_IS_HOST_MODULE),,$(LOCAL_2ND_ARCH_VAR_PREFIX),$(my_host_cross))/link_type))
+     $(call intermediates-dir-for,STATIC_LIBRARIES,$(l),$(my_kind),,$(LOCAL_2ND_ARCH_VAR_PREFIX),$(my_host_cross))/link_type))
 ifneq ($(LOCAL_MODULE_CLASS),STATIC_LIBRARIES)
 my_link_type_deps += $(strip \
    $(foreach l,$(my_shared_libraries), \
-     $(call intermediates-dir-for,SHARED_LIBRARIES,$(l),$(LOCAL_IS_HOST_MODULE),,$(LOCAL_2ND_ARCH_VAR_PREFIX),$(my_host_cross))/link_type))
+     $(call intermediates-dir-for,SHARED_LIBRARIES,$(l),$(my_kind),,$(LOCAL_2ND_ARCH_VAR_PREFIX),$(my_host_cross))/link_type))
 endif
 $(my_link_type): PRIVATE_DEPS := $(my_link_type_deps)
 $(my_link_type): PRIVATE_MODULE := $(LOCAL_MODULE)
@@ -1433,7 +1443,7 @@
 built_static_libraries := \
     $(foreach lib,$(my_static_libraries), \
       $(call intermediates-dir-for, \
-        STATIC_LIBRARIES,$(lib),$(LOCAL_IS_HOST_MODULE),,$(LOCAL_2ND_ARCH_VAR_PREFIX),$(my_host_cross))/$(lib)$(a_suffix))
+        STATIC_LIBRARIES,$(lib),$(my_kind),,$(LOCAL_2ND_ARCH_VAR_PREFIX),$(my_host_cross))/$(lib)$(a_suffix))
 
 ifdef LOCAL_SDK_VERSION
 built_static_libraries += $(my_ndk_stl_static_lib)
@@ -1442,7 +1452,7 @@
 built_whole_libraries := \
     $(foreach lib,$(my_whole_static_libraries), \
       $(call intermediates-dir-for, \
-        STATIC_LIBRARIES,$(lib),$(LOCAL_IS_HOST_MODULE),,$(LOCAL_2ND_ARCH_VAR_PREFIX),$(my_host_cross))/$(lib)$(a_suffix))
+        STATIC_LIBRARIES,$(lib),$(my_kind),,$(LOCAL_2ND_ARCH_VAR_PREFIX),$(my_host_cross))/$(lib)$(a_suffix))
 
 # We don't care about installed static libraries, since the
 # libraries have already been linked into the module at that point.
@@ -1621,15 +1631,15 @@
 # Headers exported by whole static libraries are also exported by this library.
 export_include_deps := $(strip \
    $(foreach l,$(my_whole_static_libraries), \
-     $(call intermediates-dir-for,STATIC_LIBRARIES,$(l),$(LOCAL_IS_HOST_MODULE),,$(LOCAL_2ND_ARCH_VAR_PREFIX),$(my_host_cross))/export_includes))
+     $(call intermediates-dir-for,STATIC_LIBRARIES,$(l),$(my_kind),,$(LOCAL_2ND_ARCH_VAR_PREFIX),$(my_host_cross))/export_includes))
 # Re-export requested headers from shared libraries.
 export_include_deps += $(strip \
    $(foreach l,$(LOCAL_EXPORT_SHARED_LIBRARY_HEADERS), \
-     $(call intermediates-dir-for,SHARED_LIBRARIES,$(l),$(LOCAL_IS_HOST_MODULE),,$(LOCAL_2ND_ARCH_VAR_PREFIX),$(my_host_cross))/export_includes))
+     $(call intermediates-dir-for,SHARED_LIBRARIES,$(l),$(my_kind),,$(LOCAL_2ND_ARCH_VAR_PREFIX),$(my_host_cross))/export_includes))
 # Re-export requested headers from static libraries.
 export_include_deps += $(strip \
    $(foreach l,$(LOCAL_EXPORT_STATIC_LIBRARY_HEADERS), \
-     $(call intermediates-dir-for,STATIC_LIBRARIES,$(l),$(LOCAL_IS_HOST_MODULE),,$(LOCAL_2ND_ARCH_VAR_PREFIX),$(my_host_cross))/export_includes))
+     $(call intermediates-dir-for,STATIC_LIBRARIES,$(l),$(my_kind),,$(LOCAL_2ND_ARCH_VAR_PREFIX),$(my_host_cross))/export_includes))
 $(export_includes): PRIVATE_REEXPORTED_INCLUDES := $(export_include_deps)
 # By adding $(my_generated_sources) it makes sure the headers get generated
 # before any dependent source files get compiled.
diff --git a/core/clear_vars.mk b/core/clear_vars.mk
index 6121c45..55d0021 100644
--- a/core/clear_vars.mk
+++ b/core/clear_vars.mk
@@ -142,7 +142,9 @@
 LOCAL_PROTOC_FLAGS:=
 LOCAL_PROTO_JAVA_OUTPUT_PARAMS:=
 LOCAL_NO_CRT:=
+LOCAL_NO_LIBCOMPILER_RT:=
 LOCAL_NO_LIBGCC:=
+LOCAL_NO_PIC:=
 LOCAL_PROPRIETARY_MODULE:=
 LOCAL_OEM_MODULE:=
 LOCAL_ODM_MODULE:=
@@ -363,6 +365,16 @@
 LOCAL_JAVA_LANGUAGE_VERSION:=
 LOCAL_CTS_GTEST_LIST_EXECUTABLE:=
 
+LOCAL_IS_AUX_MODULE :=
+LOCAL_AUX_TOOLCHAIN :=
+LOCAL_AUX_OS :=
+LOCAL_AUX_ARCH :=
+LOCAL_AUX_SUBARCH :=
+LOCAL_AUX_CPU :=
+LOCAL_AUX_OS_VARIANT :=
+LOCAL_CUSTOM_BUILD_STEP_INPUT:=
+LOCAL_CUSTOM_BUILD_STEP_OUTPUT:=
+
 # Trim MAKEFILE_LIST so that $(call my-dir) doesn't need to
 # iterate over thousands of entries every time.
 # Leave the current makefile to make sure we don't break anything
diff --git a/core/config.mk b/core/config.mk
index 594c273..4ad212f 100644
--- a/core/config.mk
+++ b/core/config.mk
@@ -70,6 +70,8 @@
 BUILD_HOST_STATIC_LIBRARY:= $(BUILD_SYSTEM)/host_static_library.mk
 BUILD_HOST_SHARED_LIBRARY:= $(BUILD_SYSTEM)/host_shared_library.mk
 BUILD_STATIC_LIBRARY:= $(BUILD_SYSTEM)/static_library.mk
+BUILD_AUX_STATIC_LIBRARY:= $(BUILD_SYSTEM)/aux_static_library.mk
+BUILD_AUX_EXECUTABLE:= $(BUILD_SYSTEM)/aux_executable.mk
 BUILD_SHARED_LIBRARY:= $(BUILD_SYSTEM)/shared_library.mk
 BUILD_EXECUTABLE:= $(BUILD_SYSTEM)/executable.mk
 BUILD_HOST_EXECUTABLE:= $(BUILD_SYSTEM)/host_executable.mk
diff --git a/core/definitions.mk b/core/definitions.mk
index 8ef67f1..d1284e6 100644
--- a/core/definitions.mk
+++ b/core/definitions.mk
@@ -92,6 +92,7 @@
 
 # Display names for various build targets
 TARGET_DISPLAY := target
+AUX_DISPLAY := aux
 HOST_DISPLAY := host
 HOST_CROSS_DISPLAY := host cross
 
@@ -456,6 +457,28 @@
 $(if $(1),$(call reverse-list,$(wordlist 2,$(words $(1)),$(1)))) $(firstword $(1))
 endef
 
+define def-host-aux-target
+$(eval _idf_val_:=$(if $(strip $(LOCAL_IS_HOST_MODULE)),HOST,$(if $(strip $(LOCAL_IS_AUX_MODULE)),AUX,))) \
+$(_idf_val_)
+endef
+
+###########################################################
+## Returns correct _idfPrefix from the list:
+##   { HOST, HOST_CROSS, AUX, TARGET }
+###########################################################
+# the following rules checked in order:
+# ($1 is in {AUX, HOST_CROSS} => $1;
+# ($1 is empty) => TARGET;
+# ($2 is not empty) => HOST_CROSS;
+# => HOST;
+define find-idf-prefix
+$(strip \
+    $(eval _idf_pfx_:=$(strip $(filter AUX HOST_CROSS,$(1)))) \
+    $(eval _idf_pfx_:=$(if $(strip $(1)),$(if $(_idf_pfx_),$(_idf_pfx_),$(if $(strip $(2)),HOST_CROSS,HOST)),TARGET)) \
+    $(_idf_pfx_)
+)
+endef
+
 ###########################################################
 ## The intermediates directory.  Where object files go for
 ## a given target.  We could technically get away without
@@ -466,7 +489,7 @@
 
 # $(1): target class, like "APPS"
 # $(2): target name, like "NotePad"
-# $(3): if non-empty, this is a HOST target.
+# $(3): { HOST, HOST_CROSS, AUX, <empty (TARGET)>, <other non-empty (HOST)> }
 # $(4): if non-empty, force the intermediates to be COMMON
 # $(5): if non-empty, force the intermediates to be for the 2nd arch
 # $(6): if non-empty, force the intermediates to be for the host cross os
@@ -478,7 +501,7 @@
     $(eval _idfName := $(strip $(2))) \
     $(if $(_idfName),, \
         $(error $(LOCAL_PATH): Name not defined in call to intermediates-dir-for)) \
-    $(eval _idfPrefix := $(if $(strip $(3)),$(if $(strip $(6)),HOST_CROSS,HOST),TARGET)) \
+    $(eval _idfPrefix := $(call find-idf-prefix,$(3),$(6))) \
     $(eval _idf2ndArchPrefix := $(if $(strip $(5)),$(TARGET_2ND_ARCH_VAR_PREFIX))) \
     $(if $(filter $(_idfPrefix)-$(_idfClass),$(COMMON_MODULE_CLASSES))$(4), \
         $(eval _idfIntBase := $($(_idfPrefix)_OUT_COMMON_INTERMEDIATES)) \
@@ -503,7 +526,7 @@
         $(error $(LOCAL_PATH): LOCAL_MODULE_CLASS not defined before call to local-intermediates-dir)) \
     $(if $(strip $(LOCAL_MODULE)),, \
         $(error $(LOCAL_PATH): LOCAL_MODULE not defined before call to local-intermediates-dir)) \
-    $(call intermediates-dir-for,$(LOCAL_MODULE_CLASS),$(LOCAL_MODULE),$(LOCAL_IS_HOST_MODULE),$(1),$(2),$(3)) \
+    $(call intermediates-dir-for,$(LOCAL_MODULE_CLASS),$(LOCAL_MODULE),$(call def-host-aux-target),$(1),$(2),$(3)) \
 )
 endef
 
@@ -518,7 +541,7 @@
 
 # $(1): target class, like "APPS"
 # $(2): target name, like "NotePad"
-# $(3): if non-empty, this is a HOST target.
+# $(3): { HOST, HOST_CROSS, AUX, <empty (TARGET)>, <other non-empty (HOST)> }
 # $(4): if non-empty, force the generated sources to be COMMON
 define generated-sources-dir-for
 $(strip \
@@ -528,7 +551,7 @@
     $(eval _idfName := $(strip $(2))) \
     $(if $(_idfName),, \
         $(error $(LOCAL_PATH): Name not defined in call to generated-sources-dir-for)) \
-    $(eval _idfPrefix := $(if $(strip $(3)),HOST,TARGET)) \
+    $(eval _idfPrefix := $(call find-idf-prefix,$(3),)) \
     $(if $(filter $(_idfPrefix)-$(_idfClass),$(COMMON_MODULE_CLASSES))$(4), \
         $(eval _idfIntBase := $($(_idfPrefix)_OUT_COMMON_GEN)) \
       , \
@@ -548,7 +571,7 @@
         $(error $(LOCAL_PATH): LOCAL_MODULE_CLASS not defined before call to local-generated-sources-dir)) \
     $(if $(strip $(LOCAL_MODULE)),, \
         $(error $(LOCAL_PATH): LOCAL_MODULE not defined before call to local-generated-sources-dir)) \
-    $(call generated-sources-dir-for,$(LOCAL_MODULE_CLASS),$(LOCAL_MODULE),$(LOCAL_IS_HOST_MODULE),$(1)) \
+    $(call generated-sources-dir-for,$(LOCAL_MODULE_CLASS),$(LOCAL_MODULE),$(call def-host-aux-target),$(1)) \
 )
 endef
 
@@ -1196,12 +1219,12 @@
 ifneq (,$(filter 1 true,$(WITH_TIDY_ONLY)))
 define transform-cpp-to-o
 $(if $(PRIVATE_TIDY_CHECKS),
-  @echo "target tidy $(PRIVATE_ARM_MODE) C++: $<"
+  @echo "$($(PRIVATE_PREFIX)DISPLAY) tidy $(PRIVATE_ARM_MODE) C++: $<"
   $(clang-tidy-cpp))
 endef
 else
 define transform-cpp-to-o
-@echo "target $(PRIVATE_ARM_MODE) C++: $(PRIVATE_MODULE) <= $<"
+@echo "$($(PRIVATE_PREFIX)DISPLAY) $(PRIVATE_ARM_MODE) C++: $(PRIVATE_MODULE) <= $<"
 @mkdir -p $(dir $@)
 $(if $(PRIVATE_TIDY_CHECKS),$(clang-tidy-cpp))
 $(hide) $(RELATIVE_PWD) $(PRIVATE_CXX) \
@@ -1245,12 +1268,12 @@
 ifneq (,$(filter 1 true,$(WITH_TIDY_ONLY)))
 define transform-c-to-o
 $(if $(PRIVATE_TIDY_CHECKS),
-  @echo "target tidy $(PRIVATE_ARM_MODE) C: $<"
+  @echo "$($(PRIVATE_PREFIX)DISPLAY) tidy $(PRIVATE_ARM_MODE) C: $<"
   $(clang-tidy-c))
 endef
 else
 define transform-c-to-o
-@echo "target $(PRIVATE_ARM_MODE) C: $(PRIVATE_MODULE) <= $<"
+@echo "$($(PRIVATE_PREFIX)DISPLAY) $(PRIVATE_ARM_MODE) C: $(PRIVATE_MODULE) <= $<"
 @mkdir -p $(dir $@)
 $(if $(PRIVATE_TIDY_CHECKS),$(clang-tidy-c))
 $(hide) $(RELATIVE_PWD) $(PRIVATE_CC) \
@@ -1261,7 +1284,7 @@
 endif
 
 define transform-s-to-o-no-deps
-@echo "target asm: $(PRIVATE_MODULE) <= $<"
+@echo "$($(PRIVATE_PREFIX)DISPLAY) asm: $(PRIVATE_MODULE) <= $<"
 @mkdir -p $(dir $@)
 $(RELATIVE_PWD) $(PRIVATE_CC) \
   $(call transform-c-or-s-to-o-compiler-args, $(PRIVATE_ASFLAGS)) \
@@ -1290,7 +1313,7 @@
 ###########################################################
 
 define transform-m-to-o-no-deps
-@echo "target ObjC: $(PRIVATE_MODULE) <= $<"
+@echo "$($(PRIVATE_PREFIX)DISPLAY) ObjC: $(PRIVATE_MODULE) <= $<"
 $(call transform-c-or-s-to-o-no-deps, $(PRIVATE_CFLAGS) $(PRIVATE_DEBUG_CFLAGS))
 endef
 
@@ -1549,7 +1572,7 @@
 # Explicitly delete the archive first so that ar doesn't
 # try to add to an existing archive.
 define transform-o-to-static-lib
-@echo "target StaticLib: $(PRIVATE_MODULE) ($@)"
+@echo "$($(PRIVATE_PREFIX)DISPLAY) StaticLib: $(PRIVATE_MODULE) ($@)"
 @mkdir -p $(dir $@)
 @rm -f $@
 $(extract-and-include-target-whole-static-libs)
@@ -1558,6 +1581,89 @@
     $(PRIVATE_ARFLAGS) $@,$(PRIVATE_ALL_OBJECTS))
 endef
 
+# $(1): the full path of the source static library.
+define _extract-and-include-single-aux-whole-static-lib
+$(hide) ldir=$(PRIVATE_INTERMEDIATES_DIR)/WHOLE/$(basename $(notdir $(1)))_objs;\
+    rm -rf $$ldir; \
+    mkdir -p $$ldir; \
+    cp $(1) $$ldir; \
+    lib_to_include=$$ldir/$(notdir $(1)); \
+    filelist=; \
+    subdir=0; \
+    for f in `$(PRIVATE_AR) t $(1)`; do \
+        if [ -e $$ldir/$$f ]; then \
+            mkdir $$ldir/$$subdir; \
+            ext=$$subdir/; \
+            subdir=$$((subdir+1)); \
+            $(PRIVATE_AR) m $$lib_to_include $$f; \
+        else \
+            ext=; \
+        fi; \
+        $(PRIVATE_AR) p $$lib_to_include $$f > $$ldir/$$ext$$f; \
+        filelist="$$filelist $$ldir/$$ext$$f"; \
+    done ; \
+    $(PRIVATE_AR) $(AUX_GLOBAL_ARFLAGS) \
+        $(PRIVATE_ARFLAGS) $@ $$filelist
+
+endef
+
+define extract-and-include-aux-whole-static-libs
+$(call extract-and-include-whole-static-libs-first, $(firstword $(PRIVATE_ALL_WHOLE_STATIC_LIBRARIES)))
+$(foreach lib,$(wordlist 2,999,$(PRIVATE_ALL_WHOLE_STATIC_LIBRARIES)), \
+    $(call _extract-and-include-single-aux-whole-static-lib, $(lib)))
+endef
+
+# Explicitly delete the archive first so that ar doesn't
+# try to add to an existing archive.
+define transform-o-to-aux-static-lib
+@echo "$($(PRIVATE_PREFIX)DISPLAY) StaticLib: $(PRIVATE_MODULE) ($@)"
+@mkdir -p $(dir $@)
+@rm -f $@
+$(extract-and-include-aux-whole-static-libs)
+$(call split-long-arguments,$(PRIVATE_AR) \
+    $(AUX_GLOBAL_ARFLAGS) \
+    $(PRIVATE_ARFLAGS) $@,$(PRIVATE_ALL_OBJECTS))
+endef
+
+define transform-o-to-aux-executable-inner
+$(hide) $(PRIVATE_CXX) -pie \
+	-Bdynamic \
+	-Wl,--gc-sections \
+	$(PRIVATE_ALL_OBJECTS) \
+	-Wl,--whole-archive \
+	$(call normalize-target-libraries,$(PRIVATE_ALL_WHOLE_STATIC_LIBRARIES)) \
+	-Wl,--no-whole-archive \
+	$(call normalize-target-libraries,$(PRIVATE_ALL_STATIC_LIBRARIES)) \
+	$(PRIVATE_LDFLAGS) \
+	-o $@
+endef
+
+define transform-o-to-aux-executable
+@echo "$(AUX_DISPLAY) Executable: $(PRIVATE_MODULE) ($@)"
+@mkdir -p $(dir $@)
+$(transform-o-to-aux-executable-inner)
+endef
+
+define transform-o-to-aux-static-executable-inner
+$(hide) $(PRIVATE_CXX) \
+	-Bstatic \
+	-Wl,--gc-sections \
+	$(PRIVATE_ALL_OBJECTS) \
+	-Wl,--whole-archive \
+	$(call normalize-target-libraries,$(PRIVATE_ALL_WHOLE_STATIC_LIBRARIES)) \
+	-Wl,--no-whole-archive \
+	$(call normalize-target-libraries,$(PRIVATE_ALL_STATIC_LIBRARIES)) \
+	$(PRIVATE_LDFLAGS) \
+	-Wl,-Map=$(@).map \
+	-o $@
+endef
+
+define transform-o-to-aux-static-executable
+@echo "$(AUX_DISPLAY) StaticExecutable: $(PRIVATE_MODULE) ($@)"
+@mkdir -p $(dir $@)
+$(transform-o-to-aux-static-executable-inner)
+endef
+
 ###########################################################
 ## Commands for running host ar
 ###########################################################
@@ -1702,7 +1808,7 @@
 endef
 
 define transform-o-to-shared-lib
-@echo "target SharedLib: $(PRIVATE_MODULE) ($@)"
+@echo "$($(PRIVATE_PREFIX)DISPLAY) SharedLib: $(PRIVATE_MODULE) ($@)"
 @mkdir -p $(dir $@)
 $(transform-o-to-shared-lib-inner)
 endef
@@ -1717,14 +1823,14 @@
 endif
 
 define transform-to-stripped
-@echo "target Strip: $(PRIVATE_MODULE) ($@)"
+@echo "$($(PRIVATE_PREFIX)DISPLAY) Strip: $(PRIVATE_MODULE) ($@)"
 @mkdir -p $(dir $@)
 $(hide) $(PRIVATE_STRIP) --strip-all $< -o $@ \
   $(if $(PRIVATE_NO_DEBUGLINK),,$(TARGET_STRIP_EXTRA))
 endef
 
 define transform-to-stripped-keep-mini-debug-info
-@echo "target Strip (mini debug info): $(PRIVATE_MODULE) ($@)"
+@echo "$($(PRIVATE_PREFIX)DISPLAY) Strip (mini debug info): $(PRIVATE_MODULE) ($@)"
 @mkdir -p $(dir $@)
 $(hide) $(PRIVATE_NM) -D $< --format=posix --defined-only | awk '{ print $$1 }' | sort >$@.dynsyms
 $(hide) $(PRIVATE_NM) $< --format=posix --defined-only | awk '{ if ($$2 == "T" || $$2 == "t" || $$2 == "D") print $$1 }' | sort >$@.funcsyms
@@ -1741,7 +1847,7 @@
 endef
 
 define transform-to-stripped-keep-symbols
-@echo "target Strip (keep symbols): $(PRIVATE_MODULE) ($@)"
+@echo "$($(PRIVATE_PREFIX)DISPLAY) Strip (keep symbols): $(PRIVATE_MODULE) ($@)"
 @mkdir -p $(dir $@)
 $(hide) $(PRIVATE_OBJCOPY) \
     `$(PRIVATE_READELF) -S $< | awk '/.debug_/ {print "-R " $$2}' | xargs` \
@@ -1753,7 +1859,7 @@
 ###########################################################
 
 define pack-elf-relocations
-@echo "target Pack Relocations: $(PRIVATE_MODULE) ($@)"
+@echo "$($(PRIVATE_PREFIX)DISPLAY) Pack Relocations: $(PRIVATE_MODULE) ($@)"
 $(copy-file-to-target)
 $(hide) $(RELOCATION_PACKER) $@
 endef
@@ -1790,7 +1896,7 @@
 endef
 
 define transform-o-to-executable
-@echo "target Executable: $(PRIVATE_MODULE) ($@)"
+@echo "$($(PRIVATE_PREFIX)DISPLAY) Executable: $(PRIVATE_MODULE) ($@)"
 @mkdir -p $(dir $@)
 $(transform-o-to-executable-inner)
 endef
@@ -1833,7 +1939,7 @@
 endef
 
 define transform-o-to-static-executable
-@echo "target StaticExecutable: $(PRIVATE_MODULE) ($@)"
+@echo "$($(PRIVATE_PREFIX)DISPLAY) StaticExecutable: $(PRIVATE_MODULE) ($@)"
 @mkdir -p $(dir $@)
 $(transform-o-to-static-executable-inner)
 endef
@@ -2052,7 +2158,7 @@
 endef
 
 define transform-java-to-classes.jar
-@echo "target Java: $(PRIVATE_MODULE) ($(PRIVATE_CLASS_INTERMEDIATES_DIR))"
+@echo "$($(PRIVATE_PREFIX)DISPLAY) Java: $(PRIVATE_MODULE) ($(PRIVATE_CLASS_INTERMEDIATES_DIR))"
 $(call compile-java,$(TARGET_JAVAC),$(PRIVATE_BOOTCLASSPATH))
 endef
 
@@ -2571,19 +2677,19 @@
 
 # Copy a prebuilt file to a target location.
 define transform-prebuilt-to-target
-@echo "$(if $(PRIVATE_IS_HOST_MODULE),host,target) Prebuilt: $(PRIVATE_MODULE) ($@)"
+@echo "$($(PRIVATE_PREFIX)DISPLAY) Prebuilt: $(PRIVATE_MODULE) ($@)"
 $(copy-file-to-target)
 endef
 
 # Copy a prebuilt file to a target location, using zipalign on it.
 define transform-prebuilt-to-target-with-zipalign
-@echo "$(if $(PRIVATE_IS_HOST_MODULE),host,target) Prebuilt APK: $(PRIVATE_MODULE) ($@)"
+@echo "$($(PRIVATE_PREFIX)DISPLAY) Prebuilt APK: $(PRIVATE_MODULE) ($@)"
 $(copy-file-to-target-with-zipalign)
 endef
 
 # Copy a prebuilt file to a target location, stripping "# comment" comments.
 define transform-prebuilt-to-target-strip-comments
-@echo "$(if $(PRIVATE_IS_HOST_MODULE),host,target) Prebuilt: $(PRIVATE_MODULE) ($@)"
+@echo "$($(PRIVATE_PREFIX)DISPLAY) Prebuilt: $(PRIVATE_MODULE) ($@)"
 $(copy-file-to-target-strip-comments)
 endef
 
@@ -2630,7 +2736,7 @@
 ###########################################################
 
 define transform-generated-source
-@echo "target Generated: $(PRIVATE_MODULE) <= $<"
+@echo "$($(PRIVATE_PREFIX)DISPLAY) Generated: $(PRIVATE_MODULE) <= $<"
 @mkdir -p $(dir $@)
 $(hide) $(PRIVATE_CUSTOM_TOOL)
 endef
diff --git a/core/dumpvar.mk b/core/dumpvar.mk
index 4b3486a..74ea3ff 100644
--- a/core/dumpvar.mk
+++ b/core/dumpvar.mk
@@ -22,7 +22,8 @@
   HOST_CROSS_2ND_ARCH \
   HOST_BUILD_TYPE \
   BUILD_ID \
-  OUT_DIR
+  OUT_DIR \
+  AUX_OS_VARIANT_LIST
 
 ifeq ($(TARGET_BUILD_PDK),true)
 print_build_config_vars += \
diff --git a/core/envsetup.mk b/core/envsetup.mk
index 1df25d2..f234702 100644
--- a/core/envsetup.mk
+++ b/core/envsetup.mk
@@ -273,6 +273,9 @@
 HOST_OUT_COMMON_INTERMEDIATES := $(HOST_COMMON_OUT_ROOT)/obj
 HOST_OUT_FAKE := $(HOST_OUT)/fake_packages
 
+# Nano environment config
+include $(BUILD_SYSTEM)/aux_config.mk
+
 HOST_CROSS_OUT_INTERMEDIATES := $(HOST_CROSS_OUT)/obj
 HOST_CROSS_OUT_HEADERS := $(HOST_CROSS_OUT_INTERMEDIATES)/include
 HOST_CROSS_OUT_INTERMEDIATE_LIBRARIES := $(HOST_CROSS_OUT_INTERMEDIATES)/lib
diff --git a/core/main.mk b/core/main.mk
index 59e9524..3720971 100644
--- a/core/main.mk
+++ b/core/main.mk
@@ -457,6 +457,9 @@
 $(error The 'sdk' target may not be specified with any other targets)
 endif
 
+# AUX dependencies are already added by now; remove triggers from the MAKECMDGOALS
+MAKECMDGOALS := $(strip $(filter-out AUX-%,$(MAKECMDGOALS)))
+
 # TODO: this should be eng I think.  Since the sdk is built from the eng
 # variant.
 tags_to_install := debug eng
@@ -934,6 +937,8 @@
 all_modules: $(my_all_modules)
 endif
 
+.PHONY: auxiliary
+auxiliary: $(INSTALLED_AUX_TARGETS)
 
 # Build files and then package it into the rom formats
 .PHONY: droidcore
diff --git a/core/ninja.mk b/core/ninja.mk
index 62102ba..069a43e 100644
--- a/core/ninja.mk
+++ b/core/ninja.mk
@@ -17,6 +17,7 @@
 	DUMP_% \
 	ECLIPSE-% \
 	PRODUCT-% \
+	AUX-% \
 	boottarball-nodeps \
 	brillo_tests \
 	btnod \