GYP: Don't pass -Wno-format-pedantic to GCC.

build/standalone.gypi

 # 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 394 matching lines @@
       ],
     },
     'conditions':[
       ['(clang==1 or host_clang==1) and OS!="win"', {
         # This is here so that all files get recompiled after a clang roll and
         # when turning clang on or off.
         # (defines are passed via the command line, and build systems rebuild
         # things when their commandline changes). Nothing should ever read this
         # define.
         'defines': ['CR_CLANG_REVISION=<!(<(DEPTH)/tools/clang/scripts/update.sh --print-revision)'],
-        'cflags+': [
-          '-Wno-format-pedantic',
+        'conditions': [
+          ['host_clang==1', {
+            'target_conditions': [
+              ['_toolset=="host"', {
+                'cflags+': [
+                  '-Wno-format-pedantic',
+                 ],
+              }],
+           ],
+          }],
+          ['clang==1', {
+            'target_conditions': [
+              ['_toolset=="target"', {
+                'cflags+': [
+                  '-Wno-format-pedantic',
+                 ],
+              }],
+           ],
+          }],
         ],
       }],
     ],
     'target_conditions': [
       ['v8_code == 0', {
         'defines!': [
           'DEBUG',
         ],
         'conditions': [
           ['os_posix == 1 and OS != "mac"', {
@@ skipping 861 matching lines @@
               '-fsanitize=cfi-vcall',
               '-fsanitize=cfi-derived-cast',
               '-fsanitize=cfi-unrelated-cast',
             ],
           }],
         ],
       },
     }],
   ],
 }