Issue 5433 - add option to use prebuilt v8

Makefile

 V8_DIR :=$(shell pwd -L)/third_party/v8/
 HOST_ARCH :=$(shell python ${V8_DIR}gypfiles/detect_v8_host_arch.py)
 
 GYP_PARAMETERS=host_arch=${HOST_ARCH}
 
 ifndef HOST_OS
   raw_OS = $(shell uname -s)
   ifeq (${raw_OS},Linux)
     HOST_OS=linux
   else ifeq (${raw_OS},Darwin)
     HOST_OS=mac
   endif
 endif
 
+ifneq "$(and ${LIBV8_LIB_DIR}, ${LIBV8_INCLUDE_DIR})" ""
+BUILD_V8=do-nothing
+ABP_GYP_PARAMETERS+= libv8_lib_dir=${LIBV8_LIB_DIR} libv8_include_dir=${LIBV8_INCLUDE_DIR}
+else
+BUILD_V8=build-v8
+endif
+
 ifneq ($(ANDROID_ARCH),)
 GYP_PARAMETERS+= OS=android target_arch=${ANDROID_ARCH}
 ifeq ($(ANDROID_ARCH),arm)
 ANDROID_ABI = armeabi-v7a
 else ifeq ($(ANDROID_ARCH),ia32)
 ANDROID_ABI = x86
 else
 $(error "Unsupported Android architecture: $(ANDROID_ARCH))
 endif
 ANDROID_DEST_DIR = android_$(ANDROID_ARCH).release
-else
+
+ifeq "$(and ${LIBV8_LIB_DIR}, ${LIBV8_INCLUDE_DIR})" ""
+ABP_GYP_PARAMETERS+= libv8_lib_dir=${ANDROID_DEST_DIR}
+BUILD_V8=build-v8-android
+endif
+
+else # if ${ANDROID_ARCH} is empty
 TARGET_ARCH=${HOST_ARCH}
 ifdef ARCH
 TARGET_ARCH=${ARCH}
 endif
 GYP_PARAMETERS+= OS=${HOST_OS} target_arch=${TARGET_ARCH}
 endif
 
 
 TEST_EXECUTABLE = build/out/Debug/tests
 
-.PHONY: all test clean docs v8 v8_android_multi android_multi android_x86 \
+.PHONY: do-nothing all test clean docs build-v8 build-v8-android v8_android_multi android_multi android_x86 \
         android_arm ensure_dependencies
 
 .DEFAULT_GOAL:=all
 
+do-nothing:
+
 ensure_dependencies:
         python ensure_dependencies.py
 
-v8: ensure_dependencies
+build-v8: ensure_dependencies
         GYP_DEFINES="${GYP_PARAMETERS}" third_party/gyp/gyp --depth=. -f make -I build-v8.gypi --generator-output=build/v8 ${V8_DIR}src/v8.gyp
         make -C build/v8 v8_snapshot v8_libplatform v8_libsampler
 
-all: v8
-        GYP_DEFINES="${GYP_PARAMETERS}" third_party/gyp/gyp --depth=. -f make -I libadblockplus.gypi --generator-output=build libadblockplus.gyp
+all: ${BUILD_V8} ensure_dependencies 
+        GYP_DEFINES="${GYP_PARAMETERS} ${ABP_GYP_PARAMETERS}" third_party/gyp/gyp --depth=. -f make -I libadblockplus.gypi --generator-output=build libadblockplus.gyp
         $(MAKE) -C build
 
 test: all
 ifdef FILTER
         $(TEST_EXECUTABLE) --gtest_filter=$(FILTER)
 else
         $(TEST_EXECUTABLE)
 endif
 
 docs:
@@ skipping 27 matching lines @@
           builddir=${V8_DIR}../../build/android_${ANDROID_ARCH}.release
 
 v8_android_multi_linux_${ANDROID_ARCH}: v8_android_multi
 
 v8_android_multi_mac_ia32: v8_android_multi
         find build/android_ia32.release/ -depth 1 -iname \*.a -exec ${ANDROID_NDK_ROOT}/toolchains/x86-4.9/prebuilt/darwin-x86_64/bin/i686-linux-android-ranlib {} \;
 
 v8_android_multi_mac_arm: v8_android_multi
         find build/android_arm.release/ -depth 1 -iname \*.a -exec ${ANDROID_NDK_ROOT}/toolchains/arm-linux-androideabi-4.9/prebuilt/darwin-x86_64/bin/arm-linux-androideabi-ranlib {} \;
 
-android_multi: v8_android_multi_${HOST_OS}_${ANDROID_ARCH}
-        GYP_DEFINES="${GYP_PARAMETERS}" \
+build-v8-android: v8_android_multi_${HOST_OS}_${ANDROID_ARCH}
+
+android_multi: ${BUILD_V8} ensure_dependencies
+        GYP_DEFINES="${GYP_PARAMETERS} ${ABP_GYP_PARAMETERS}" \
         python ./make_gyp_wrapper.py --depth=. -f make-android -Ilibadblockplus.gypi --generator-output=build -Gandroid_ndk_version=r9 libadblockplus.gyp
         $(ANDROID_NDK_ROOT)/ndk-build -C build installed_modules \
         BUILDTYPE=Release \
         APP_ABI=$(ANDROID_ABI) \
         APP_PLATFORM=android-9 \
         APP_STL=c++_static \
         APP_BUILD_SCRIPT=Makefile \
         NDK_PROJECT_PATH=. \
         NDK_OUT=. \
         NDK_APP_DST_DIR=$(ANDROID_DEST_DIR)
 endif