Add public libs from an environment variable

This is enabled only for builds with ro.debuggable=1
It is intended for use only in tests using dalvikvm
and needing access to platform libraries.

Bug: http://b/28449304
Change-Id: I402457d0da542996ccf265aeaa305f09881e4333
(cherry picked from commit 4ddabd01bf361cadb33baa7213e2ca5129b938f0)
diff --git a/libnativeloader/Android.mk b/libnativeloader/Android.mk
index 6c064c7..632c6c8 100644
--- a/libnativeloader/Android.mk
+++ b/libnativeloader/Android.mk
@@ -1,19 +1,21 @@
 LOCAL_PATH:= $(call my-dir)
 
-NATIVE_LOADER_COMMON_SRC_FILES := \
+native_loader_common_src_files := \
   native_loader.cpp
 
+native_loader_common_cflags := -Werror -Wall
+
 # Shared library for target
 # ========================================================
 include $(CLEAR_VARS)
 
 LOCAL_MODULE:= libnativeloader
 
-LOCAL_SRC_FILES:= $(NATIVE_LOADER_COMMON_SRC_FILES)
+LOCAL_SRC_FILES:= $(native_loader_common_src_files)
 LOCAL_SHARED_LIBRARIES := libnativehelper liblog libcutils
 LOCAL_STATIC_LIBRARIES := libbase
 LOCAL_CLANG := true
-LOCAL_CFLAGS += -Werror -Wall
+LOCAL_CFLAGS := $(native_loader_common_cflags)
 LOCAL_CPPFLAGS := -std=gnu++14 -fvisibility=hidden
 LOCAL_LDFLAGS := -ldl
 LOCAL_MULTILIB := both
@@ -27,11 +29,11 @@
 
 LOCAL_MODULE:= libnativeloader
 
-LOCAL_SRC_FILES:= $(NATIVE_LOADER_COMMON_SRC_FILES)
+LOCAL_SRC_FILES:= $(native_loader_common_src_files)
 LOCAL_SHARED_LIBRARIES := libnativehelper liblog libcutils
 LOCAL_STATIC_LIBRARIES := libbase
 LOCAL_CLANG := true
-LOCAL_CFLAGS += -Werror -Wall
+LOCAL_CFLAGS := $(native_loader_common_cflags)
 LOCAL_CPPFLAGS := -std=gnu++14 -fvisibility=hidden
 LOCAL_LDFLAGS := -ldl
 LOCAL_MULTILIB := both
@@ -45,10 +47,10 @@
 
 LOCAL_MODULE:= libnativeloader
 
-LOCAL_SRC_FILES:= $(NATIVE_LOADER_COMMON_SRC_FILES)
+LOCAL_SRC_FILES:= $(native_loader_common_src_files)
 LOCAL_STATIC_LIBRARIES := libnativehelper libcutils liblog libbase
 LOCAL_CLANG := true
-LOCAL_CFLAGS += -Werror -Wall
+LOCAL_CFLAGS := $(native_loader_common_cflags)
 LOCAL_CPPFLAGS := -std=gnu++14 -fvisibility=hidden
 LOCAL_LDFLAGS := -ldl
 LOCAL_MULTILIB := both