Add build system infrastructure for ENABLE_EXTRA_CHECKS flag (not used yet)

Review URL: https://chromiumcodereview.appspot.com/10905093

git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@12440 ce2b1a6d-e550-0410-aec6-3dcde31c8c00

Makefile

@@ -62,6 +62,13 @@ endif
 ifeq ($(snapshot), off)
   GYPFLAGS += -Dv8_use_snapshot='false'
 endif
+# extrachecks=on/off
+ifeq ($(extrachecks), on)
+  GYPFLAGS += -Dv8_enable_extra_checks=1
+endif
+ifeq ($(extrachecks), off)
+  GYPFLAGS += -Dv8_enable_extra_checks=0
+endif
 # gdbjit=on
 ifeq ($(gdbjit), on)
   GYPFLAGS += -Dv8_enable_gdbjit=1

build/common.gypi

@@ -70,6 +70,9 @@
 
     'v8_enable_disassembler%': 0,
 
+    # Enable extra checks in API functions and other strategic places.
+    'v8_enable_extra_checks%' 1,
+
     'v8_object_print%': 0,
 
     'v8_enable_gdbjit%': 0,
@@ -109,6 +112,9 @@
       ['v8_enable_disassembler==1', {
         'defines': ['ENABLE_DISASSEMBLER',],
       }],
+      ['v8_enable_extra_checks==1', {
+        'defines': ['ENABLE_EXTRA_CHECKS',],
+      }],
       ['v8_object_print==1', {
         'defines': ['OBJECT_PRINT',],
       }],