Make the gyp files more cross-platform across the Unices

ui/base/strings/ui_strings.gyp

 {
   'variables': {
     'chromium_code': 1,
     'grit_base_out_dir': '<(SHARED_INTERMEDIATE_DIR)/app',
   },
   'targets': [
     {
       'target_name': 'ui_strings',
       'type': 'none',
       'msvs_guid': 'BC3C49A3-D061-4E78-84EE-742DA064DC46',
@@ skipping 22 matching lines @@
         ],
       },
       'conditions': [
         ['OS=="win"', {
           'dependencies': ['../../../build/win/system.gyp:cygwin'],
         }],
       ],
     },
   ],
   'conditions': [
-    ['OS=="linux" or OS=="freebsd" or OS=="openbsd" or OS=="solaris"', {
+    ['os_posix==1 and OS!="mac"', {
       'targets': [{
         'target_name': 'ui_unittest_strings',
         'type': 'none',
         'variables': {
           'repack_path': '<(DEPTH)/tools/data_pack/repack.py',
         },
         'actions': [
           {
             'action_name': 'repack_ui_unittest_strings',
             'variables': {
@@ skipping 18 matching lines @@
             'destination': '<(PRODUCT_DIR)/app_unittests_strings',
             'files': [
               '<(grit_base_out_dir)/app_resources/app_resources.pak',
             ],
           },
         ],
       }],
     }],
   ],
 }