diff --git a/buildspec.mk.default b/buildspec.mk.default
index d14208e..3224d1a 100644
--- a/buildspec.mk.default
+++ b/buildspec.mk.default
@@ -61,9 +61,6 @@
 # will be added to LOCAL_CFLAGS when building the module.
 #DEBUG_MODULE_ModuleName:=true
 
-# Specify an alternative tool chain prefix if needed.
-#TARGET_TOOLS_PREFIX:=
-
 # Specify the extra CFLAGS to use when building a module whose
 # DEBUG_MODULE_ variable is set.  Host and device flags are handled
 # separately.
diff --git a/core/clang/config.mk b/core/clang/config.mk
index 7b4821a..c7499ab 100644
--- a/core/clang/config.mk
+++ b/core/clang/config.mk
@@ -3,11 +3,6 @@
 LLVM_PREBUILTS_PATH := $(LLVM_PREBUILTS_BASE)/$(BUILD_OS)-x86/$(LLVM_PREBUILTS_VERSION)/bin
 LLVM_RTLIB_PATH := $(LLVM_PREBUILTS_PATH)/../lib64/clang/$(LLVM_RELEASE_VERSION)/lib/linux/
 
-CLANG := $(LLVM_PREBUILTS_PATH)/clang$(BUILD_EXECUTABLE_SUFFIX)
-CLANG_CXX := $(LLVM_PREBUILTS_PATH)/clang++$(BUILD_EXECUTABLE_SUFFIX)
-LLVM_AS := $(LLVM_PREBUILTS_PATH)/llvm-as$(BUILD_EXECUTABLE_SUFFIX)
-LLVM_LINK := $(LLVM_PREBUILTS_PATH)/llvm-link$(BUILD_EXECUTABLE_SUFFIX)
-
 CLANG_TBLGEN := $(BUILD_OUT_EXECUTABLES)/clang-tblgen$(BUILD_EXECUTABLE_SUFFIX)
 LLVM_TBLGEN := $(BUILD_OUT_EXECUTABLES)/llvm-tblgen$(BUILD_EXECUTABLE_SUFFIX)
 
diff --git a/core/combo/HOST_CROSS_windows-x86.mk b/core/combo/HOST_CROSS_windows-x86.mk
index 6180a26..fd1db6f 100644
--- a/core/combo/HOST_CROSS_windows-x86.mk
+++ b/core/combo/HOST_CROSS_windows-x86.mk
@@ -22,7 +22,6 @@
 $(combo_var_prefix)GLOBAL_CFLAGS += --sysroot prebuilts/gcc/linux-x86/host/x86_64-w64-mingw32-4.8/x86_64-w64-mingw32
 $(combo_var_prefix)GLOBAL_CFLAGS += -m32
 $(combo_var_prefix)GLOBAL_LDFLAGS += -m32
-TOOLS_PREFIX := prebuilts/gcc/linux-x86/host/x86_64-w64-mingw32-4.8/bin/x86_64-w64-mingw32-
 $(combo_var_prefix)C_INCLUDES += prebuilts/gcc/linux-x86/host/x86_64-w64-mingw32-4.8/x86_64-w64-mingw32/include
 $(combo_var_prefix)C_INCLUDES += prebuilts/gcc/linux-x86/host/x86_64-w64-mingw32-4.8/lib/gcc/x86_64-w64-mingw32/4.8.3/include
 $(combo_var_prefix)GLOBAL_LD_DIRS += -Lprebuilts/gcc/linux-x86/host/x86_64-w64-mingw32-4.8/x86_64-w64-mingw32/lib32
@@ -37,12 +36,6 @@
 # Get 64-bit off_t and related functions.
 $(combo_var_prefix)GLOBAL_CFLAGS += -D_FILE_OFFSET_BITS=64
 
-$(combo_var_prefix)CC := $(TOOLS_PREFIX)gcc
-$(combo_var_prefix)CXX := $(TOOLS_PREFIX)g++
-$(combo_var_prefix)AR := $(TOOLS_PREFIX)ar
-$(combo_var_prefix)NM := $(TOOLS_PREFIX)nm
-$(combo_var_prefix)OBJDUMP := $(TOOLS_PREFIX)objdump
-
 define $(combo_var_prefix)transform-shared-lib-to-toc
 $(hide) $($(PRIVATE_2ND_ARCH_VAR_PREFIX)$(PRIVATE_PREFIX)OBJDUMP) -x $(1) | grep "^Name" | cut -f3 -d" " > $(2)
 $(hide) $($(PRIVATE_2ND_ARCH_VAR_PREFIX)$(PRIVATE_PREFIX)NM) -g -f p $(1) | cut -f1-2 -d" " >> $(2)
diff --git a/core/combo/HOST_CROSS_windows-x86_64.mk b/core/combo/HOST_CROSS_windows-x86_64.mk
index e9b19cf..aee4582 100644
--- a/core/combo/HOST_CROSS_windows-x86_64.mk
+++ b/core/combo/HOST_CROSS_windows-x86_64.mk
@@ -22,7 +22,6 @@
 $(combo_var_prefix)GLOBAL_CFLAGS += --sysroot prebuilts/gcc/linux-x86/host/x86_64-w64-mingw32-4.8/x86_64-w64-mingw32
 $(combo_var_prefix)GLOBAL_CFLAGS += -m64
 $(combo_var_prefix)GLOBAL_LDFLAGS += -m64
-TOOLS_PREFIX := prebuilts/gcc/linux-x86/host/x86_64-w64-mingw32-4.8/bin/x86_64-w64-mingw32-
 $(combo_var_prefix)C_INCLUDES += prebuilts/gcc/linux-x86/host/x86_64-w64-mingw32-4.8/x86_64-w64-mingw32/include
 $(combo_var_prefix)C_INCLUDES += prebuilts/gcc/linux-x86/host/x86_64-w64-mingw32-4.8/lib/gcc/x86_64-w64-mingw32/4.8.3/include
 $(combo_var_prefix)GLOBAL_LD_DIRS += -Lprebuilts/gcc/linux-x86/host/x86_64-w64-mingw32-4.8/x86_64-w64-mingw32/lib64
@@ -37,12 +36,6 @@
 # Get 64-bit off_t and related functions.
 $(combo_var_prefix)GLOBAL_CFLAGS += -D_FILE_OFFSET_BITS=64
 
-$(combo_var_prefix)CC := $(TOOLS_PREFIX)gcc
-$(combo_var_prefix)CXX := $(TOOLS_PREFIX)g++
-$(combo_var_prefix)AR := $(TOOLS_PREFIX)ar
-$(combo_var_prefix)NM := $(TOOLS_PREFIX)nm
-$(combo_var_prefix)OBJDUMP := $(TOOLS_PREFIX)objdump
-
 define $(combo_var_prefix)transform-shared-lib-to-toc
 $(hide) $($(PRIVATE_2ND_ARCH_VAR_PREFIX)$(PRIVATE_PREFIX)OBJDUMP) -x $(1) | grep "^Name" | cut -f3 -d" " > $(2)
 $(hide) $($(PRIVATE_2ND_ARCH_VAR_PREFIX)$(PRIVATE_PREFIX)NM) -g -f p $(1) | cut -f1-2 -d" " >> $(2)
diff --git a/core/combo/HOST_darwin-x86.mk b/core/combo/HOST_darwin-x86.mk
index ea384b4..575a455 100644
--- a/core/combo/HOST_darwin-x86.mk
+++ b/core/combo/HOST_darwin-x86.mk
@@ -31,21 +31,10 @@
 
 include $(BUILD_COMBOS)/mac_version.mk
 
-$(combo_2nd_arch_prefix)HOST_TOOLCHAIN_ROOT := prebuilts/gcc/darwin-x86/host/i686-apple-darwin-4.2.1
-$(combo_2nd_arch_prefix)HOST_TOOLCHAIN_PREFIX := $($(combo_2nd_arch_prefix)HOST_TOOLCHAIN_ROOT)/bin/i686-apple-darwin11
-$(combo_2nd_arch_prefix)HOST_CC  := $($(combo_2nd_arch_prefix)HOST_TOOLCHAIN_PREFIX)-gcc
-$(combo_2nd_arch_prefix)HOST_CXX := $($(combo_2nd_arch_prefix)HOST_TOOLCHAIN_PREFIX)-g++
-
 define $(combo_var_prefix)transform-shared-lib-to-toc
 $(call _gen_toc_command_for_macho,$(1),$(2))
 endef
 
-# gcc location for clang; to be updated when clang is updated
-# HOST_TOOLCHAIN_ROOT is a Darwin-specific define
-$(combo_2nd_arch_prefix)HOST_TOOLCHAIN_FOR_CLANG := $($(combo_2nd_arch_prefix)HOST_TOOLCHAIN_ROOT)
-
-$(combo_2nd_arch_prefix)HOST_AR := $(mac_sdk_path)/Toolchains/XcodeDefault.xctoolchain/usr/bin/ar
-
 $(combo_2nd_arch_prefix)HOST_GLOBAL_CFLAGS += -isysroot $(mac_sdk_root) -mmacosx-version-min=$(mac_sdk_version) -DMACOSX_DEPLOYMENT_TARGET=$(mac_sdk_version)
 $(combo_2nd_arch_prefix)HOST_GLOBAL_LDFLAGS += -isysroot $(mac_sdk_root) -Wl,-syslibroot,$(mac_sdk_root) -mmacosx-version-min=$(mac_sdk_version)
 
diff --git a/core/combo/HOST_darwin-x86_64.mk b/core/combo/HOST_darwin-x86_64.mk
index eee2ee5..6531e38 100644
--- a/core/combo/HOST_darwin-x86_64.mk
+++ b/core/combo/HOST_darwin-x86_64.mk
@@ -31,21 +31,10 @@
 
 include $(BUILD_COMBOS)/mac_version.mk
 
-HOST_TOOLCHAIN_ROOT := prebuilts/gcc/darwin-x86/host/i686-apple-darwin-4.2.1
-HOST_TOOLCHAIN_PREFIX := $(HOST_TOOLCHAIN_ROOT)/bin/i686-apple-darwin11
-HOST_CC  := $(HOST_TOOLCHAIN_PREFIX)-gcc
-HOST_CXX := $(HOST_TOOLCHAIN_PREFIX)-g++
-
 define $(combo_var_prefix)transform-shared-lib-to-toc
 $(call _gen_toc_command_for_macho,$(1),$(2))
 endef
 
-# gcc location for clang; to be updated when clang is updated
-# HOST_TOOLCHAIN_ROOT is a Darwin-specific define
-HOST_TOOLCHAIN_FOR_CLANG := $(HOST_TOOLCHAIN_ROOT)
-
-HOST_AR := $(mac_sdk_path)/Toolchains/XcodeDefault.xctoolchain/usr/bin/ar
-
 HOST_GLOBAL_CFLAGS += -isysroot $(mac_sdk_root) -mmacosx-version-min=$(mac_sdk_version) -DMACOSX_DEPLOYMENT_TARGET=$(mac_sdk_version)
 HOST_GLOBAL_LDFLAGS += -isysroot $(mac_sdk_root) -Wl,-syslibroot,$(mac_sdk_root) -mmacosx-version-min=$(mac_sdk_version)
 
diff --git a/core/combo/HOST_linux-x86.mk b/core/combo/HOST_linux-x86.mk
index 169e2d2..48ed0ba 100644
--- a/core/combo/HOST_linux-x86.mk
+++ b/core/combo/HOST_linux-x86.mk
@@ -17,15 +17,6 @@
 # Configuration for builds hosted on linux-x86.
 # Included by combo/select.mk
 
-ifeq ($(strip $($(combo_2nd_arch_prefix)HOST_TOOLCHAIN_PREFIX)),)
-$(combo_2nd_arch_prefix)HOST_TOOLCHAIN_PREFIX := prebuilts/gcc/linux-x86/host/x86_64-linux-glibc2.15-4.8/bin/x86_64-linux-
-endif
-$(combo_2nd_arch_prefix)HOST_CC  := $($(combo_2nd_arch_prefix)HOST_TOOLCHAIN_PREFIX)gcc
-$(combo_2nd_arch_prefix)HOST_CXX := $($(combo_2nd_arch_prefix)HOST_TOOLCHAIN_PREFIX)g++
-$(combo_2nd_arch_prefix)HOST_AR  := $($(combo_2nd_arch_prefix)HOST_TOOLCHAIN_PREFIX)ar
-$(combo_2nd_arch_prefix)HOST_READELF  := $($(combo_2nd_arch_prefix)HOST_TOOLCHAIN_PREFIX)readelf
-$(combo_2nd_arch_prefix)HOST_NM  := $($(combo_2nd_arch_prefix)HOST_TOOLCHAIN_PREFIX)nm
-
 define $(combo_var_prefix)transform-shared-lib-to-toc
 $(call _gen_toc_command_for_elf,$(1),$(2))
 endef
diff --git a/core/combo/HOST_linux-x86_64.mk b/core/combo/HOST_linux-x86_64.mk
index 9766f2b..faa7238 100644
--- a/core/combo/HOST_linux-x86_64.mk
+++ b/core/combo/HOST_linux-x86_64.mk
@@ -17,15 +17,6 @@
 # Configuration for builds hosted on linux-x86_64.
 # Included by combo/select.mk
 
-ifeq ($(strip $(HOST_TOOLCHAIN_PREFIX)),)
-HOST_TOOLCHAIN_PREFIX := prebuilts/gcc/linux-x86/host/x86_64-linux-glibc2.15-4.8/bin/x86_64-linux-
-endif
-HOST_CC  := $(HOST_TOOLCHAIN_PREFIX)gcc
-HOST_CXX := $(HOST_TOOLCHAIN_PREFIX)g++
-HOST_AR  := $(HOST_TOOLCHAIN_PREFIX)ar
-HOST_READELF  := $(HOST_TOOLCHAIN_PREFIX)readelf
-HOST_NM  := $(HOST_TOOLCHAIN_PREFIX)nm
-
 define $(combo_var_prefix)transform-shared-lib-to-toc
 $(call _gen_toc_command_for_elf,$(1),$(2))
 endef
diff --git a/core/combo/TARGET_linux-arm.mk b/core/combo/TARGET_linux-arm.mk
index e2d42cc..dee04e0 100644
--- a/core/combo/TARGET_linux-arm.mk
+++ b/core/combo/TARGET_linux-arm.mk
@@ -36,11 +36,7 @@
 # Decouple NDK library selection with platform compiler version
 $(combo_2nd_arch_prefix)TARGET_NDK_GCC_VERSION := 4.9
 
-ifeq ($(strip $(TARGET_GCC_VERSION_EXP)),)
 $(combo_2nd_arch_prefix)TARGET_GCC_VERSION := 4.9
-else
-$(combo_2nd_arch_prefix)TARGET_GCC_VERSION := $(TARGET_GCC_VERSION_EXP)
-endif
 
 TARGET_ARCH_SPECIFIC_MAKEFILE := $(BUILD_COMBOS)/arch/$(TARGET_$(combo_2nd_arch_prefix)ARCH)/$(TARGET_$(combo_2nd_arch_prefix)ARCH_VARIANT).mk
 ifeq ($(strip $(wildcard $(TARGET_ARCH_SPECIFIC_MAKEFILE))),)
@@ -50,20 +46,7 @@
 include $(TARGET_ARCH_SPECIFIC_MAKEFILE)
 include $(BUILD_SYSTEM)/combo/fdo.mk
 
-# You can set TARGET_TOOLS_PREFIX to get gcc from somewhere else
-ifeq ($(strip $($(combo_2nd_arch_prefix)TARGET_TOOLS_PREFIX)),)
 $(combo_2nd_arch_prefix)TARGET_TOOLCHAIN_ROOT := prebuilts/gcc/$(HOST_PREBUILT_TAG)/arm/arm-linux-androideabi-$($(combo_2nd_arch_prefix)TARGET_GCC_VERSION)
-$(combo_2nd_arch_prefix)TARGET_TOOLS_PREFIX := $($(combo_2nd_arch_prefix)TARGET_TOOLCHAIN_ROOT)/bin/arm-linux-androideabi-
-endif
-
-$(combo_2nd_arch_prefix)TARGET_CC := $($(combo_2nd_arch_prefix)TARGET_TOOLS_PREFIX)gcc
-$(combo_2nd_arch_prefix)TARGET_CXX := $($(combo_2nd_arch_prefix)TARGET_TOOLS_PREFIX)g++
-$(combo_2nd_arch_prefix)TARGET_AR := $($(combo_2nd_arch_prefix)TARGET_TOOLS_PREFIX)ar
-$(combo_2nd_arch_prefix)TARGET_OBJCOPY := $($(combo_2nd_arch_prefix)TARGET_TOOLS_PREFIX)objcopy
-$(combo_2nd_arch_prefix)TARGET_LD := $($(combo_2nd_arch_prefix)TARGET_TOOLS_PREFIX)ld
-$(combo_2nd_arch_prefix)TARGET_READELF := $($(combo_2nd_arch_prefix)TARGET_TOOLS_PREFIX)readelf
-$(combo_2nd_arch_prefix)TARGET_STRIP := $($(combo_2nd_arch_prefix)TARGET_TOOLS_PREFIX)strip
-$(combo_2nd_arch_prefix)TARGET_NM := $($(combo_2nd_arch_prefix)TARGET_TOOLS_PREFIX)nm
 
 define $(combo_var_prefix)transform-shared-lib-to-toc
 $(call _gen_toc_command_for_elf,$(1),$(2))
diff --git a/core/combo/TARGET_linux-arm64.mk b/core/combo/TARGET_linux-arm64.mk
index c027113..4ff921b 100644
--- a/core/combo/TARGET_linux-arm64.mk
+++ b/core/combo/TARGET_linux-arm64.mk
@@ -36,11 +36,7 @@
 # Decouple NDK library selection with platform compiler version
 TARGET_NDK_GCC_VERSION := 4.9
 
-ifeq ($(strip $(TARGET_GCC_VERSION_EXP)),)
 TARGET_GCC_VERSION := 4.9
-else
-TARGET_GCC_VERSION := $(TARGET_GCC_VERSION_EXP)
-endif
 
 TARGET_ARCH_SPECIFIC_MAKEFILE := $(BUILD_COMBOS)/arch/$(TARGET_ARCH)/$(TARGET_ARCH_VARIANT).mk
 ifeq ($(strip $(wildcard $(TARGET_ARCH_SPECIFIC_MAKEFILE))),)
@@ -50,20 +46,7 @@
 include $(TARGET_ARCH_SPECIFIC_MAKEFILE)
 include $(BUILD_SYSTEM)/combo/fdo.mk
 
-# You can set TARGET_TOOLS_PREFIX to get gcc from somewhere else
-ifeq ($(strip $(TARGET_TOOLS_PREFIX)),)
 TARGET_TOOLCHAIN_ROOT := prebuilts/gcc/$(HOST_PREBUILT_TAG)/aarch64/aarch64-linux-android-$(TARGET_GCC_VERSION)
-TARGET_TOOLS_PREFIX := $(TARGET_TOOLCHAIN_ROOT)/bin/aarch64-linux-android-
-endif
-
-TARGET_CC := $(TARGET_TOOLS_PREFIX)gcc
-TARGET_CXX := $(TARGET_TOOLS_PREFIX)g++
-TARGET_AR := $(TARGET_TOOLS_PREFIX)ar
-TARGET_OBJCOPY := $(TARGET_TOOLS_PREFIX)objcopy
-TARGET_LD := $(TARGET_TOOLS_PREFIX)ld
-TARGET_READELF := $(TARGET_TOOLS_PREFIX)readelf
-TARGET_STRIP := $(TARGET_TOOLS_PREFIX)strip
-TARGET_NM := $(TARGET_TOOLS_PREFIX)nm
 
 define $(combo_var_prefix)transform-shared-lib-to-toc
 $(call _gen_toc_command_for_elf,$(1),$(2))
diff --git a/core/combo/TARGET_linux-mips.mk b/core/combo/TARGET_linux-mips.mk
index d872a4a..4ce6b81 100644
--- a/core/combo/TARGET_linux-mips.mk
+++ b/core/combo/TARGET_linux-mips.mk
@@ -36,11 +36,7 @@
 # Decouple NDK library selection with platform compiler version
 $(combo_2nd_arch_prefix)TARGET_NDK_GCC_VERSION := 4.9
 
-ifeq ($(strip $(TARGET_GCC_VERSION_EXP)),)
 $(combo_2nd_arch_prefix)TARGET_GCC_VERSION := 4.9
-else
-$(combo_2nd_arch_prefix)TARGET_GCC_VERSION := $(TARGET_GCC_VERSION_EXP)
-endif
 
 TARGET_ARCH_SPECIFIC_MAKEFILE := $(BUILD_COMBOS)/arch/$(TARGET_$(combo_2nd_arch_prefix)ARCH)/$(TARGET_$(combo_2nd_arch_prefix)ARCH_VARIANT).mk
 ifeq ($(strip $(wildcard $(TARGET_ARCH_SPECIFIC_MAKEFILE))),)
@@ -50,20 +46,7 @@
 include $(TARGET_ARCH_SPECIFIC_MAKEFILE)
 include $(BUILD_SYSTEM)/combo/fdo.mk
 
-# You can set TARGET_TOOLS_PREFIX to get gcc from somewhere else
-ifeq ($(strip $($(combo_2nd_arch_prefix)TARGET_TOOLS_PREFIX)),)
 $(combo_2nd_arch_prefix)TARGET_TOOLCHAIN_ROOT := prebuilts/gcc/$(HOST_PREBUILT_TAG)/mips/mips64el-linux-android-$($(combo_2nd_arch_prefix)TARGET_GCC_VERSION)
-$(combo_2nd_arch_prefix)TARGET_TOOLS_PREFIX := $($(combo_2nd_arch_prefix)TARGET_TOOLCHAIN_ROOT)/bin/mips64el-linux-android-
-endif
-
-$(combo_2nd_arch_prefix)TARGET_CC := $($(combo_2nd_arch_prefix)TARGET_TOOLS_PREFIX)gcc
-$(combo_2nd_arch_prefix)TARGET_CXX := $($(combo_2nd_arch_prefix)TARGET_TOOLS_PREFIX)g++
-$(combo_2nd_arch_prefix)TARGET_AR := $($(combo_2nd_arch_prefix)TARGET_TOOLS_PREFIX)ar
-$(combo_2nd_arch_prefix)TARGET_OBJCOPY := $($(combo_2nd_arch_prefix)TARGET_TOOLS_PREFIX)objcopy
-$(combo_2nd_arch_prefix)TARGET_LD := $($(combo_2nd_arch_prefix)TARGET_TOOLS_PREFIX)ld
-$(combo_2nd_arch_prefix)TARGET_READELF := $($(combo_2nd_arch_prefix)TARGET_TOOLS_PREFIX)readelf
-$(combo_2nd_arch_prefix)TARGET_STRIP := $($(combo_2nd_arch_prefix)TARGET_TOOLS_PREFIX)strip
-$(combo_2nd_arch_prefix)TARGET_NM := $($(combo_2nd_arch_prefix)TARGET_TOOLS_PREFIX)nm
 
 define $(combo_var_prefix)transform-shared-lib-to-toc
 $(call _gen_toc_command_for_elf,$(1),$(2))
diff --git a/core/combo/TARGET_linux-mips64.mk b/core/combo/TARGET_linux-mips64.mk
index 32128b2..6683b5d 100644
--- a/core/combo/TARGET_linux-mips64.mk
+++ b/core/combo/TARGET_linux-mips64.mk
@@ -36,11 +36,7 @@
 # Decouple NDK library selection with platform compiler version
 TARGET_NDK_GCC_VERSION := 4.9
 
-ifeq ($(strip $(TARGET_GCC_VERSION_EXP)),)
 TARGET_GCC_VERSION := 4.9
-else
-TARGET_GCC_VERSION := $(TARGET_GCC_VERSION_EXP)
-endif
 
 TARGET_ARCH_SPECIFIC_MAKEFILE := $(BUILD_COMBOS)/arch/$(TARGET_ARCH)/$(TARGET_ARCH_VARIANT).mk
 ifeq ($(strip $(wildcard $(TARGET_ARCH_SPECIFIC_MAKEFILE))),)
@@ -50,20 +46,7 @@
 include $(TARGET_ARCH_SPECIFIC_MAKEFILE)
 include $(BUILD_SYSTEM)/combo/fdo.mk
 
-# You can set TARGET_TOOLS_PREFIX to get gcc from somewhere else
-ifeq ($(strip $(TARGET_TOOLS_PREFIX)),)
 TARGET_TOOLCHAIN_ROOT := prebuilts/gcc/$(HOST_PREBUILT_TAG)/mips/mips64el-linux-android-$(TARGET_GCC_VERSION)
-TARGET_TOOLS_PREFIX := $(TARGET_TOOLCHAIN_ROOT)/bin/mips64el-linux-android-
-endif
-
-TARGET_CC := $(TARGET_TOOLS_PREFIX)gcc
-TARGET_CXX := $(TARGET_TOOLS_PREFIX)g++
-TARGET_AR := $(TARGET_TOOLS_PREFIX)ar
-TARGET_OBJCOPY := $(TARGET_TOOLS_PREFIX)objcopy
-TARGET_LD := $(TARGET_TOOLS_PREFIX)ld
-TARGET_READELF := $(TARGET_TOOLS_PREFIX)readelf
-TARGET_STRIP := $(TARGET_TOOLS_PREFIX)strip
-TARGET_NM := $(TARGET_TOOLS_PREFIX)nm
 
 define $(combo_var_prefix)transform-shared-lib-to-toc
 $(call _gen_toc_command_for_elf,$(1),$(2))
diff --git a/core/combo/TARGET_linux-x86.mk b/core/combo/TARGET_linux-x86.mk
index 1f27502..aaa39b7 100644
--- a/core/combo/TARGET_linux-x86.mk
+++ b/core/combo/TARGET_linux-x86.mk
@@ -25,11 +25,7 @@
 # Decouple NDK library selection with platform compiler version
 $(combo_2nd_arch_prefix)TARGET_NDK_GCC_VERSION := 4.9
 
-ifeq ($(strip $(TARGET_GCC_VERSION_EXP)),)
 $(combo_2nd_arch_prefix)TARGET_GCC_VERSION := 4.9
-else
-$(combo_2nd_arch_prefix)TARGET_GCC_VERSION := $(TARGET_GCC_VERSION_EXP)
-endif
 
 # Include the arch-variant-specific configuration file.
 # Its role is to define various ARCH_X86_HAVE_XXX feature macros,
@@ -43,20 +39,7 @@
 include $(TARGET_ARCH_SPECIFIC_MAKEFILE)
 include $(BUILD_SYSTEM)/combo/fdo.mk
 
-# You can set TARGET_TOOLS_PREFIX to get gcc from somewhere else
-ifeq ($(strip $($(combo_2nd_arch_prefix)TARGET_TOOLS_PREFIX)),)
 $(combo_2nd_arch_prefix)TARGET_TOOLCHAIN_ROOT := prebuilts/gcc/$(HOST_PREBUILT_TAG)/x86/x86_64-linux-android-$($(combo_2nd_arch_prefix)TARGET_GCC_VERSION)
-$(combo_2nd_arch_prefix)TARGET_TOOLS_PREFIX := $($(combo_2nd_arch_prefix)TARGET_TOOLCHAIN_ROOT)/bin/x86_64-linux-android-
-endif
-
-$(combo_2nd_arch_prefix)TARGET_CC := $($(combo_2nd_arch_prefix)TARGET_TOOLS_PREFIX)gcc
-$(combo_2nd_arch_prefix)TARGET_CXX := $($(combo_2nd_arch_prefix)TARGET_TOOLS_PREFIX)g++
-$(combo_2nd_arch_prefix)TARGET_AR := $($(combo_2nd_arch_prefix)TARGET_TOOLS_PREFIX)ar
-$(combo_2nd_arch_prefix)TARGET_OBJCOPY := $($(combo_2nd_arch_prefix)TARGET_TOOLS_PREFIX)objcopy
-$(combo_2nd_arch_prefix)TARGET_LD := $($(combo_2nd_arch_prefix)TARGET_TOOLS_PREFIX)ld
-$(combo_2nd_arch_prefix)TARGET_READELF := $($(combo_2nd_arch_prefix)TARGET_TOOLS_PREFIX)readelf
-$(combo_2nd_arch_prefix)TARGET_STRIP := $($(combo_2nd_arch_prefix)TARGET_TOOLS_PREFIX)strip
-$(combo_2nd_arch_prefix)TARGET_NM := $($(combo_2nd_arch_prefix)TARGET_TOOLS_PREFIX)nm
 
 define $(combo_var_prefix)transform-shared-lib-to-toc
 $(call _gen_toc_command_for_elf,$(1),$(2))
diff --git a/core/combo/TARGET_linux-x86_64.mk b/core/combo/TARGET_linux-x86_64.mk
index ea6550b..b26a0ab 100644
--- a/core/combo/TARGET_linux-x86_64.mk
+++ b/core/combo/TARGET_linux-x86_64.mk
@@ -25,11 +25,7 @@
 # Decouple NDK library selection with platform compiler version
 TARGET_NDK_GCC_VERSION := 4.9
 
-ifeq ($(strip $(TARGET_GCC_VERSION_EXP)),)
 TARGET_GCC_VERSION := 4.9
-else
-TARGET_GCC_VERSION := $(TARGET_GCC_VERSION_EXP)
-endif
 
 # Include the arch-variant-specific configuration file.
 # Its role is to define various ARCH_X86_HAVE_XXX feature macros,
@@ -43,20 +39,7 @@
 include $(TARGET_ARCH_SPECIFIC_MAKEFILE)
 include $(BUILD_SYSTEM)/combo/fdo.mk
 
-# You can set TARGET_TOOLS_PREFIX to get gcc from somewhere else
-ifeq ($(strip $(TARGET_TOOLS_PREFIX)),)
 TARGET_TOOLCHAIN_ROOT := prebuilts/gcc/$(HOST_PREBUILT_TAG)/x86/x86_64-linux-android-$(TARGET_GCC_VERSION)
-TARGET_TOOLS_PREFIX := $(TARGET_TOOLCHAIN_ROOT)/bin/x86_64-linux-android-
-endif
-
-TARGET_CC := $(TARGET_TOOLS_PREFIX)gcc
-TARGET_CXX := $(TARGET_TOOLS_PREFIX)g++
-TARGET_AR := $(TARGET_TOOLS_PREFIX)ar
-TARGET_OBJCOPY := $(TARGET_TOOLS_PREFIX)objcopy
-TARGET_LD := $(TARGET_TOOLS_PREFIX)ld
-TARGET_READELF := $(TARGET_TOOLS_PREFIX)readelf
-TARGET_STRIP := $(TARGET_TOOLS_PREFIX)strip
-TARGET_NM := $(TARGET_TOOLS_PREFIX)nm
 
 define $(combo_var_prefix)transform-shared-lib-to-toc
 $(call _gen_toc_command_for_elf,$(1),$(2))
diff --git a/core/combo/select.mk b/core/combo/select.mk
index df12e7e..54ea2da 100644
--- a/core/combo/select.mk
+++ b/core/combo/select.mk
@@ -28,11 +28,6 @@
 
 # Set reasonable defaults for the various variables
 
-$(combo_var_prefix)CC := $(CC)
-$(combo_var_prefix)CXX := $(CXX)
-$(combo_var_prefix)AR := $(AR)
-$(combo_var_prefix)STRIP := $(STRIP)
-
 $(combo_var_prefix)GLOBAL_CFLAGS := -fno-exceptions -Wno-multichar
 $(combo_var_prefix)RELEASE_CFLAGS := -O2 -g -fno-strict-aliasing
 $(combo_var_prefix)GLOBAL_CPPFLAGS :=
diff --git a/core/config.mk b/core/config.mk
index 516fec8..1f06af4 100644
--- a/core/config.mk
+++ b/core/config.mk
@@ -329,14 +329,6 @@
 TARGET_CPU_ABI_LIST_32_BIT := $(subst $(space),$(comma),$(strip $(TARGET_CPU_ABI_LIST_32_BIT)))
 TARGET_CPU_ABI_LIST_64_BIT := $(subst $(space),$(comma),$(strip $(TARGET_CPU_ABI_LIST_64_BIT)))
 
-# Compute TARGET_TOOLCHAIN_ROOT from TARGET_TOOLS_PREFIX
-# if only TARGET_TOOLS_PREFIX is passed to the make command.
-ifndef TARGET_TOOLCHAIN_ROOT
-TARGET_TOOLCHAIN_ROOT := $(patsubst %/, %, $(dir $(TARGET_TOOLS_PREFIX)))
-TARGET_TOOLCHAIN_ROOT := $(patsubst %/, %, $(dir $(TARGET_TOOLCHAIN_ROOT)))
-TARGET_TOOLCHAIN_ROOT := $(wildcard $(TARGET_TOOLCHAIN_ROOT))
-endif
-
 # Normalize WITH_STATIC_ANALYZER and WITH_SYNTAX_CHECK
 ifeq ($(strip $(WITH_STATIC_ANALYZER)),0)
   WITH_STATIC_ANALYZER :=