Allow GCC to build Skia on Mac.

gyp/common_conditions.gypi

Index: gyp/common_conditions.gypi
diff --git a/gyp/common_conditions.gypi b/gyp/common_conditions.gypi
index 4d06ffcc14221ea1fd4f85941b15a4fc8e127458..d9c048771e0b75373fc2fbbb02224887684a5096 100644
--- a/gyp/common_conditions.gypi
+++ b/gyp/common_conditions.gypi
@@ -506,10 +506,12 @@
           'GCC_ENABLE_SUPPLEMENTAL_SSE3_INSTRUCTIONS': 'YES',  # -mssse3
           'GCC_SYMBOLS_PRIVATE_EXTERN':                'NO',   # -fvisibility=hidden
           'GCC_INLINES_ARE_PRIVATE_EXTERN':            'NO',   # -fvisibility-inlines-hidden
+          'GCC_CW_ASM_SYNTAX':                         'NO',   # remove -fasm-blocks
+          'GCC_ENABLE_PASCAL_STRINGS':                 'NO',   # remove -mpascal-strings
+          'GCC_WARN_ABOUT_INVALID_OFFSETOF_MACRO':     'NO',   # -Wno-invalid-offsetof
           'WARNING_CFLAGS': [
             '-Wall',
             '-Wextra',
-            '-Wno-invalid-offsetof',
             '-Wno-unused-parameter',
             '-Wno-uninitialized',  # Disabled because we think GCC 4.2 is bad at this.
           ],
@@ -551,8 +553,8 @@
           'IPHONEOS_DEPLOYMENT_TARGET': '<(ios_sdk_version)',
           'SDKROOT': 'iphoneos',
           'TARGETED_DEVICE_FAMILY': '1,2',
+          'GCC_WARN_ABOUT_INVALID_OFFSETOF_MACRO': 'NO',   # -Wno-invalid-offsetof
           'OTHER_CPLUSPLUSFLAGS': [
-            '-Wno-invalid-offsetof',
             '-fvisibility=hidden',
             '-fvisibility-inlines-hidden',
           ],