Fix "make arm asan=$CLANG"

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 122 matching lines @@
   GYPFLAGS += -Dv8_enable_i18n_support=0
   TESTFLAGS += --noi18n
 endif
 # deprecation_warnings=on
 ifeq ($(deprecationwarnings), on)
   GYPFLAGS += -Dv8_deprecation_warnings=1
 endif
 # asan=/path/to/clang++
 ifneq ($(strip $(asan)),)
   GYPFLAGS += -Dasan=1
-  export CXX="$(asan)"
-  export CXX_host="$(asan)"
-  export LINK="$(asan)"
+  export CXX=$(asan)
+  export CXX_host=$(asan)
+  export LINK=$(asan)
   export ASAN_SYMBOLIZER_PATH="$(dir $(asan))llvm-symbolizer"
 endif
 
 # arm specific flags.
 # arm_version=<number | "default">
 ifneq ($(strip $(arm_version)),)
   GYPFLAGS += -Darm_version=$(arm_version)
 else
 # Deprecated (use arm_version instead): armv7=false/true
 ifeq ($(armv7), false)
@@ skipping 312 matching lines @@
         @$(OUTDIR)/ia32.release/d8 --dump-heap-constants >> $(DUMP_FILE)
 
 # Dependencies.
 # Remember to keep these in sync with the DEPS file.
 dependencies:
         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