Make optimizations for debug configurable with compile flag.

To turn on optimizations for debug when building standalone, a compiler flag can be used:

make optdebug=on

R=jkummerow@chromium.org

Review URL: https://codereview.chromium.org/19164003

git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@15678 ce2b1a6d-e550-0410-aec6-3dcde31c8c00

Makefile

@@ -91,6 +91,10 @@ endif
 ifeq ($(vtunejit), on)
   GYPFLAGS += -Dv8_enable_vtunejit=1
 endif
+# optdebug=on
+ifeq ($(optdebug), on)
+  GYPFLAGS += -Dv8_optimized_debug=1
+endif
 # debuggersupport=off
 ifeq ($(debuggersupport), off)
   GYPFLAGS += -Dv8_enable_debugger_support=0