introduce android_x64 build target

Makefile.android

 # Copyright 2012 the V8 project authors. All rights reserved.
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 # OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 
 # Those definitions should be consistent with the main Makefile
-ANDROID_ARCHES = android_ia32 android_arm android_arm64 android_mipsel android_x87
+ANDROID_ARCHES = android_ia32 android_x64 android_arm android_arm64 \
+                 android_mipsel android_x87
 MODES = release debug
 
 # Generates all combinations of ANDROID ARCHES and MODES,
 # e.g. "android_ia32.release" or "android_arm.release"
 ANDROID_BUILDS = $(foreach mode,$(MODES), \
                    $(addsuffix .$(mode),$(ANDROID_ARCHES)))
 
 HOST_OS = $(shell uname -s | sed -e 's/Linux/linux/;s/Darwin/mac/')
 ANDROID_NDK_HOST_ARCH ?= $(shell uname -m | sed -e 's/i[3456]86/x86/')
 ifeq ($(HOST_OS), linux)
@@ skipping 19 matching lines @@
   DEFINES  = target_arch=mipsel v8_target_arch=mipsel android_target_platform=14
   DEFINES += android_target_arch=mips mips_arch_variant=mips32r2
   TOOLCHAIN_ARCH = mipsel-linux-android
   TOOLCHAIN_PREFIX = $(TOOLCHAIN_ARCH)
   TOOLCHAIN_VER = 4.8
 else ifeq ($(ARCH), android_ia32)
   DEFINES = target_arch=ia32 v8_target_arch=ia32 android_target_arch=x86 android_target_platform=14
   TOOLCHAIN_ARCH = x86
   TOOLCHAIN_PREFIX = i686-linux-android
   TOOLCHAIN_VER = 4.8
+else ifeq ($(ARCH), android_x64)
+  DEFINES = target_arch=x64 v8_target_arch=x64 android_target_arch=x86_64 android_target_platform=21
+  TOOLCHAIN_ARCH = x86_64
+  TOOLCHAIN_PREFIX = x86_64-linux-android
+  TOOLCHAIN_VER = 4.9
 else ifeq ($(ARCH), android_x87)
   DEFINES = target_arch=x87 v8_target_arch=x87 android_target_arch=x86 android_target_platform=14
   TOOLCHAIN_ARCH = x86
   TOOLCHAIN_PREFIX = i686-linux-android
   TOOLCHAIN_VER = 4.8
 else
   $(error Target architecture "${ARCH}" is not supported)
 endif
 
 TOOLCHAIN_PATH = \
@@ skipping 27 matching lines @@
 ANDROID_MAKEFILES = $(addprefix $(OUTDIR)/Makefile.,$(ANDROID_BUILDS))
 $(ANDROID_MAKEFILES):
         GYP_GENERATORS=make-android \
         GYP_DEFINES="${DEFINES}" \
         CC="${ANDROID_TOOLCHAIN}/bin/${TOOLCHAIN_PREFIX}-gcc" \
         CXX="${ANDROID_TOOLCHAIN}/bin/${TOOLCHAIN_PREFIX}-g++" \
         PYTHONPATH="$(shell pwd)/tools/generate_shim_headers:$(shell pwd)/build:$(PYTHONPATH)" \
         build/gyp/gyp --generator-output="${OUTDIR}" build/all.gyp \
                       -Ibuild/standalone.gypi --depth=. -Ibuild/android.gypi \
                       -S$(suffix $(basename $@))$(suffix $@) ${GYPFLAGS}