Bug 407600 - Compile Spidermonkey with -Os on Mac, r=bsmedberg, no approval needed, NPOTB

js/src/config.mk

@@ -117,7 +117,11 @@ CP = cp
 endif
 
 ifdef BUILD_OPT
-OPTIMIZER  = -O
+ifdef USE_MSVC
+OPTIMIZER  = -O1
+else
+OPTIMIZER  = -Os
+endif
 DEFINES    += -UDEBUG -DNDEBUG -UDEBUG_$(USER)
 OBJDIR_TAG = _OPT
 else