Turn more warnings on, including

- unused functions
- unused locals
- sign mismatch
- missing function prototypes
- missing newline at end of file
- 64 to 32 bit truncation
Review URL: https://codereview.appspot.com/6307043

git-svn-id: http://skia.googlecode.com/svn/trunk@4190 2bbb7eff-a529-9590-31e7-b0007b416f81

gyp/common_conditions.gypi

@@ -133,6 +133,24 @@
 # trying to get this to work, but it needs clang I think...
 #          'WARNING_CFLAGS': '-Wexit-time-destructors',
           'CLANG_WARN_CXX0X_EXTENSIONS': 'NO',
+          'GCC_WARN_64_TO_32_BIT_CONVERSION': 'YES',
+          'GCC_WARN_ABOUT_DEPRECATED_FUNCTIONS': 'YES',
+          'GCC_WARN_ABOUT_INVALID_OFFSETOF_MACRO': 'YES',
+          'GCC_WARN_ABOUT_MISSING_NEWLINE': 'YES',
+          'GCC_WARN_ABOUT_MISSING_PROTOTYPES': 'YES',
+          'GCC_WARN_ABOUT_POINTER_SIGNEDNESS': 'YES',
+          'GCC_WARN_ABOUT_RETURN_TYPE': 'YES',
+          'GCC_WARN_ALLOW_INCOMPLETE_PROTOCOL': 'YES',
+          'GCC_WARN_INITIALIZER_NOT_FULLY_BRACKETED': 'YES',
+          'GCC_WARN_MISSING_PARENTHESES': 'YES',
+          'GCC_WARN_PROTOTYPE_CONVERSION': 'YES',
+          'GCC_WARN_SIGN_COMPARE': 'YES',
+          'GCC_WARN_TYPECHECK_CALLS_TO_PRINTF': 'YES',
+          'GCC_WARN_UNKNOWN_PRAGMAS': 'YES',
+          'GCC_WARN_UNUSED_FUNCTION': 'YES',
+          'GCC_WARN_UNUSED_LABEL': 'YES',
+          'GCC_WARN_UNUSED_VALUE': 'YES',
+          'GCC_WARN_UNUSED_VARIABLE': 'YES',
           'OTHER_CPLUSPLUSFLAGS': '-mssse3 -fvisibility=hidden -fvisibility-inlines-hidden',
         },
       },