fiddle_build_test depends on skia_mesa

gyp/tools.gyp

 # Copyright 2015 Google Inc.
 #
 # Use of this source code is governed by a BSD-style license that can be
 # found in the LICENSE file.
     # GYP file to build various tools.
 #
 # To build on Linux:
 #  ./gyp_skia tools.gyp && make tools
 #
 {
@@ skipping 16 matching lines @@
         'lua_pictures',
         'pinspect',
         'skdiff',
         'skhello',
         'skpinfo',
         'skpmaker',
         'test_public_includes',
         'whitelist_typefaces',
       ],
       'conditions': [
-        # ['skia_os == "linux"', { 'dependencies': [ 'fiddle_build_test' ] } ],
+        ['skia_mesa and skia_os in ["linux", "mac"]',
+          { 'dependencies': [ 'fiddle_build_test' ] }
+        ],
         ['skia_shared_lib',
           {
             'dependencies': [
               'sklua', # This can only be built if skia is built as a shared library
             ],
           },
         ],
         [ 'skia_os == "android"',
           {
             'dependencies': [
@@ skipping 557 matching lines @@
               'pdf.gyp:pdf',
             ],
             'defines': [ 'FIDDLE_BUILD_TEST' ],
             'link_settings': { 'libraries': [ '-lOSMesa' ], },
           },
         ],
       },
     ],
   ],
 }