Enable Ozone software implementation in GYP

build/linux/system.gyp

 # Copyright (c) 2012 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.
 
 {
   'variables': {
     'conditions': [
       ['sysroot!=""', {
         'pkg-config': './pkg-config-wrapper "<(sysroot)" "<(target_arch)"',
       }, {
@@ skipping 851 matching lines @@
             'ldflags': [
               '<!@(<(pkg-config) --libs-only-L --libs-only-other libudev)',
             ],
             'libraries': [
               '<!@(<(pkg-config) --libs-only-l libudev)',
             ],
           },
         }],
       ],
     },
+    {
+      'target_name': 'dridrm',
+      'type': 'none',
+      'direct_dependent_settings': {
+        'cflags': [
+          '<!@(<(pkg-config) --cflags libdrm)',
+        ],
+      },
+      'link_settings': {
+        'libraries': [
+          '<!@(<(pkg-config) --libs-only-l libdrm)',
+        ],
+      },
+    },
   ],
 }