fixes to linux build for webtry

experimental/webtry/templates/template.gyp

 {
   'targets': [
     {
       'configurations': {
         'Debug': { },
         'Release': { }
       },
+      'cflags!': [
+        '-Werror'
+      ],
       'target_name': '{{.Hash}}',
       'type': 'executable',
       'dependencies': [
         '../skia/gyp/skia_lib.gyp:skia_lib',
         '../skia/gyp/flags.gyp:flags'
       ],
       'include_dirs': [
         '../skia/include/config',
         '../skia/include/core',
         '../skia/tools/flags',
         '../skia/src/core',
       ],
       'conditions': [
         ['skia_os == "mac"', {
                 'defines': ['SK_UNSAFE_BUILD_DESKTOP_ONLY=1']
         }]
       ],
       'sources': [
         'src/{{.Hash}}.cpp',
         '../skia/experimental/webtry/main.cpp'
       ],
-      'ldflags': [
-        '-lskia', '-stdlib=libc++', '-std=c++11'
-      ],
-      'cflags': [
-        '-Werror', '-W', '-Wall', '-Wextra', '-Wno-unused-parameter', '-g', '-O0'
-      ]
     }
   ]
 }