Fix remaining CXX cross-compilation builds in Makefile.

r22509 fixed arm and mips (big-endian) cross-compilation builds.

It did not fix mipsel, mips64el, or arm64 builds, since the
toolchain prefix did not match the v8_target_arch.

For mips, the toolchain is typically named mips-linux-gnu-g++,
but it can compile for mipsel or mips64el via flags. (There can
also be mipsel-linux-gnu-g++ toolchains, and this patch will
work for mipsel build in that case).

For arm64, the toolchains seem to be named aarch64-linux-gnu-g++.

BUG=
R=jkummerow@chromium.org

Review URL: https://codereview.chromium.org/408133002

git-svn-id: https://v8.googlecode.com/svn/branches/bleeding_edge@22531 ce2b1a6d-e550-0410-aec6-3dcde31c8c00

Makefile

@@ -401,14 +401,15 @@ 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 "-" ))
+	$(eval CXX_TARGET_ARCH:=$(subst aarch64,arm64,$CXX_TARGET_ARCH))
 	$(eval V8_TARGET_ARCH:=$(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="$(OUTDIR)" build/all.gyp \
 	              -Ibuild/standalone.gypi --depth=. \
 	              -Dv8_target_arch=$(V8_TARGET_ARCH) \
-	              $(if $(filter $(CXX_TARGET_ARCH),$(V8_TARGET_ARCH)), \
-	              -Dtarget_arch=$(CXX_TARGET_ARCH),) \
+	              $(if $(findstring $(CXX_TARGET_ARCH),$(V8_TARGET_ARCH)), \
+	              -Dtarget_arch=$(V8_TARGET_ARCH),) \
 	              $(if $(findstring optdebug,$@),-Dv8_optimized_debug=2,) \
 	              -S$(suffix $(basename $@))$(suffix $@) $(GYPFLAGS)