add system libXNVCtrl library support in linux unbundle

build/linux/unbundle/libXNVCtrl.gyp

Index: build/linux/unbundle/libXNVCtrl.gyp
diff --git a/build/linux/unbundle/libpng.gyp b/build/linux/unbundle/libXNVCtrl.gyp
similarity index 57%
copy from build/linux/unbundle/libpng.gyp
copy to build/linux/unbundle/libXNVCtrl.gyp
index d6933fc22ac291dc200b4f7148d45dadba49241f..37543293ddb6e324a4c2672e2ce62fdbdbdb38f6 100644
--- a/build/linux/unbundle/libpng.gyp
+++ b/build/linux/unbundle/libXNVCtrl.gyp
@@ -1,38 +1,35 @@
-# Copyright 2013 The Chromium Authors. All rights reserved.
+# Copyright (c) 2013 The Chromium Authors. All rights reserved.
 # Use of this source code is governed by a BSD-style license that can be
 # found in the LICENSE file.
 
 {
   'targets': [
     {
-      'target_name': 'libpng',
+      'target_name': 'libXNVCtrl',
       'type': 'none',
-      'dependencies': [
-        '../zlib/zlib.gyp:zlib',
+      'variables': {
+        'headers_root_path': '.',
+        'header_filenames': [
+          'NVCtrlLib.h',
+          'NVCtrl.h',
+        ],
+      },
+      'includes': [
+        '../../build/shim_headers.gypi',
       ],
       'direct_dependent_settings': {
         'cflags': [
-          '<!@(pkg-config --cflags libpng)',
+            '<!@(pkg-config --cflags libXNVCtrl)',
         ],
       },
       'link_settings': {
         'ldflags': [
-          '<!@(pkg-config --libs-only-L --libs-only-other libpng)',
+          '<!@(pkg-config --libs-only-L --libs-only-other libXNVCtrl)',
         ],
         'libraries': [
-          '<!@(pkg-config --libs-only-l libpng)',
+          '<!@(pkg-config --libs-only-l libXNVCtrl)',
         ],
       },
-      'variables': {
-        'headers_root_path': '.',
-        'header_filenames': [
-          'png.h',
-          'pngconf.h',
-        ],
-      },
-      'includes': [
-        '../../build/shim_headers.gypi',
-      ],
-    },
+    }
   ],
 }