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

This flag is not understood correctly by GCC and breaks the GCC ARM and MIPS optdebug builds.

Patch from Brendan Kirby <brendan.kirby@imgtec.com>

BUG=

Review URL: https://codereview.chromium.org/1369273003

Cr-Commit-Position: refs/heads/master@{#31013}

build/standalone.gypi

@@ -412,8 +412,25 @@
         # 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',
+                 ],
+              }],
+           ],
+          }],
         ],
       }],
     ],