Fixing some warnings on Linux

gyp/common_conditions.gypi

 # conditions used in both common.gypi and skia.gyp in chromium
 #
 {
   'defines': [
     'SK_ALLOW_STATIC_GLOBAL_INITIALIZERS=<(skia_static_initializers)',
 #    'SK_SUPPORT_HINTING_SCALE_FACTOR',
   ],
   'conditions' : [
     ['skia_gpu == 1',
       {
@@ skipping 122 matching lines @@
         'configurations': {
           'Debug': {
             'cflags': ['-g']
           },
           'Release': {
             'cflags': ['-O3 -g'],
             'defines': [ 'NDEBUG' ],
           },
         },
         'cflags': [
-          # TODO(tony): Enable -Werror once all the strict-aliasing problems
-          # are fixed.
-          #'-Werror',
+          '-Werror',
           '-Wall',
           '-Wextra',
-          '-Wno-unused',
           # suppressions below here were added for clang
           '-Wno-unused-parameter',
           '-Wno-c++11-extensions'
         ],
         'conditions' : [
           ['skia_warnings_as_errors == 1', {
             'cflags': [
               '-Werror',
             ],
           }],
@@ skipping 228 matching lines @@
   'xcode_settings': {
     'SYMROOT': '<(DEPTH)/xcodebuild',
   },
 }
 
 # Local Variables:
 # tab-width:2
 # indent-tabs-mode:nil
 # End:
 # vim: set expandtab tabstop=2 shiftwidth=2: