only the linux app needs 'copy-styles'

- works around make xproj error (gyp generator bug?) with nested paths that leads to 'assert group_ref.__class__ == PBXGroup'

gyp/styles.gypi

@@ -21,16 +21,6 @@
       'direct_dependent_settings': {
         'mac_bundle_resources': [ '../styles/styles' ],
       }
-    },
-    {
-      'target_name': 'copy_styles',
-      'type': 'none',
-      'hard_dependency': 1,
-      'dependencies': [ 'touch_styles' ], # required for xcode http://openradar.appspot.com/7232149
-      'copies': [{
-        'files': [ '../styles' ],
-        'destination': '<(PRODUCT_DIR)'
-      }],
-    },
+    }
   ]
 }

linux/mapboxgl-app.gyp

@@ -3,6 +3,16 @@
     '../gyp/common.gypi',
   ],
   'targets': [
+    {
+      'target_name': 'copy_styles',
+      'type': 'none',
+      'hard_dependency': 1,
+      'dependencies': [ '../styles.gyp:touch_styles' ], # required for xcode http://openradar.appspot.com/7232149
+      'copies': [{
+        'files': [ '../styles/styles' ],
+        'destination': '<(PRODUCT_DIR)'
+      }],
+    },
     {
       'target_name': 'linuxapp',
       'product_name': 'mapbox-gl',
@@ -42,9 +52,9 @@
         }]
       ],
       'dependencies': [
+        'copy_styles',
         '../mapboxgl.gyp:mbgl-standalone',
         '../mapboxgl.gyp:mbgl-linux',
-        '../mapboxgl.gyp:copy_styles',
         '../mapboxgl.gyp:copy_certificate_bundle',
       ],
     },