Add CXX cross-compile detection into Makefile after it was removed from gyp.

Makefile

 # 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 381 matching lines @@
 native.clean:
         rm -f $(OUTDIR)/Makefile.native
         rm -rf $(OUTDIR)/native
         find $(OUTDIR) -regex '.*\(host\|target\)\.native\.mk' -delete
 
 clean: $(addsuffix .clean, $(ARCHES) $(ANDROID_ARCHES) $(NACL_ARCHES)) native.clean gtags.clean
 
 # GYP file generation targets.
 OUT_MAKEFILES = $(addprefix $(OUTDIR)/Makefile.,$(BUILDS))
 $(OUT_MAKEFILES): $(GYPFILES) $(ENVFILE)
+        $(eval CXX_TARGET_ARCH:=$(shell $(CXX) -v 2>&1 | grep ^Target: | \
+                cut -f 2 -d " " | cut -f 1 -d "-" ))
+        $(eval V8_TARGET_ARCH:=$(subst .,,$(suffix $(basename $@))))
         PYTHONPATH="$(shell pwd)/tools/generate_shim_headers:$(shell pwd)/build:$(PYTHONPATH):$(shell pwd)/build/gyp/pylib:$(PYTHONPATH)" \
         GYP_GENERATORS=make \
         build/gyp/gyp --generator-output="$(OUTDIR)" build/all.gyp \
                       -Ibuild/standalone.gypi --depth=. \
-                      -Dv8_target_arch=$(subst .,,$(suffix $(basename $@))) \
+                      -Dv8_target_arch=$(V8_TARGET_ARCH) \
+                      $(if $(filter $(CXX_TARGET_ARCH),$(V8_TARGET_ARCH)), \
+                      -Dtarget_arch=$(CXX_TARGET_ARCH),) \
                       $(if $(findstring optdebug,$@),-Dv8_optimized_debug=2,) \
                       -S$(suffix $(basename $@))$(suffix $@) $(GYPFLAGS)
 
 $(OUTDIR)/Makefile.native: $(GYPFILES) $(ENVFILE)
         PYTHONPATH="$(shell pwd)/tools/generate_shim_headers:$(shell pwd)/build:$(PYTHONPATH):$(shell pwd)/build/gyp/pylib:$(PYTHONPATH)" \
         GYP_GENERATORS=make \
         build/gyp/gyp --generator-output="$(OUTDIR)" build/all.gyp \
                       -Ibuild/standalone.gypi --depth=. -S.native $(GYPFLAGS)
 
 must-set-ANDROID_NDK_ROOT_OR_TOOLCHAIN:
@@ skipping 51 matching lines @@
 builddeps:
         svn checkout --force http://gyp.googlecode.com/svn/trunk build/gyp \
             --revision 1831
         svn checkout --force \
             https://src.chromium.org/chrome/trunk/deps/third_party/icu46 \
             third_party/icu --revision 258359
 
 dependencies: builddeps
         # The spec is a copy of the hooks in v8's DEPS file.
         gclient sync -r fb782d4369d5ae04f17a2fceef7de5a63e50f07b --spec="solutions = [{u'managed': False, u'name': u'buildtools', u'url': u'https://chromium.googlesource.com/chromium/buildtools.git', u'custom_deps': {}, u'custom_hooks': [{u'name': u'clang_format_win',u'pattern': u'.',u'action': [u'download_from_google_storage',u'--no_resume',u'--platform=win32',u'--no_auth',u'--bucket',u'chromium-clang-format',u'-s',u'buildtools/win/clang-format.exe.sha1']},{u'name': u'clang_format_mac',u'pattern': u'.',u'action': [u'download_from_google_storage',u'--no_resume',u'--platform=darwin',u'--no_auth',u'--bucket',u'chromium-clang-format',u'-s',u'buildtools/mac/clang-format.sha1']},{u'name': u'clang_format_linux',u'pattern': u'.',u'action': [u'download_from_google_storage',u'--no_resume',u'--platform=linux*',u'--no_auth',u'--bucket',u'chromium-clang-format',u'-s',u'buildtools/linux64/clang-format.sha1']}],u'deps_file': u'.DEPS.git', u'safesync_url': u''}]"