Enable building for android on x86_64 machines.

Makefile.android

 # Copyright 2012 the V8 project authors. All rights reserved.
 # Redistribution and use in source and binary forms, with or without
 # modification, are permitted provided that the following conditions are
 # met:
 #
 #     * Redistributions of source code must retain the above copyright
 #       notice, this list of conditions and the following disclaimer.
 #     * Redistributions in binary form must reproduce the above
 #       copyright notice, this list of conditions and the following
 #       disclaimer in the documentation and/or other materials provided
@@ skipping 18 matching lines @@
 ANDROID_ARCHES = android_ia32 android_arm android_mipsel
 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 = $(shell uname -s | sed -e 's/Linux/linux/;s/Darwin/mac/')
 ifeq ($(HOST_OS), linux)
-  TOOLCHAIN_DIR = linux-x86
+  HOST_ARCH = $(shell uname -m | \

[ulan, 2013/07/16 09:04:14]

This doesn't work with previous versions of Android NDK (pre r8e), which  had
only x86. For example, I have x86_64 machine, but the host arch is linux-x86
(android-ndk-r8d). Maybe it is better to allow the user to enable x86_64 via
parameter like we allow to specify ${ANDROID_NDK_ROOT}?

[rmcilroy, 2013/07/16 16:44:28]

How about this?  It defaults this variable based on the host's arch, but it can
be override if required by setting ANDROID_NDK_HOST_ARCH.

+                sed -e 's/i386/x86/;s/i486/x86/;s/i586/x86/;s/i686/x86/;')
+  TOOLCHAIN_DIR = linux-$(HOST_ARCH)
 else
   ifeq ($(HOST_OS), mac)
     TOOLCHAIN_DIR = darwin-x86
   else
     $(error Host platform "${HOST_OS}" is not supported)
   endif
 endif
 
 ifeq ($(ARCH), android_arm)
   DEFINES  = target_arch=arm v8_target_arch=arm android_target_arch=arm
@@ skipping 39 matching lines @@
 # Android GYP file generation targets.
 ANDROID_MAKEFILES = $(addprefix $(OUTDIR)/Makefile.,$(ANDROID_ARCHES))
 $(ANDROID_MAKEFILES):
         @GYP_GENERATORS=make-android \
         GYP_DEFINES="${DEFINES}" \
         CC="${ANDROID_TOOLCHAIN}/bin/*-gcc" \
         CXX="${ANDROID_TOOLCHAIN}/bin/*-g++" \
         build/gyp/gyp --generator-output="${OUTDIR}" build/all.gyp \
                       -Ibuild/standalone.gypi --depth=. -Ibuild/android.gypi \
                       -S.${ARCH} ${GYPFLAGS}