Speculative revert to fix ChromeOS PFQ mips builder

third_party/libexif/libexif.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': [
       ['OS == "linux" and chromeos==0', {
         'use_system_libexif%': 1,
       }, {  # OS != "linux" and chromeos==0
@@ skipping 96 matching lines @@
               'msvs_settings': {
                 'VCCLCompilerTool': {
                   'AdditionalOptions!': [ '/analyze' ]
                 },
               },
             }],
           ],
         },
       ],
     }, { # 'use_system_libexif!=0
+      'conditions': [
+        ['sysroot!=""', {
+          'variables': {
+            'pkg-config': '../../build/linux/pkg-config-wrapper "<(sysroot)" "<(target_arch)" "<(system_libdir)"',
+          },
+        }, {
+          'variables': {
+            'pkg-config': 'pkg-config'
+          },
+        }],
+      ],
       'targets': [
         {
           'target_name': 'libexif',
           'type': 'none',
           'direct_dependent_settings': {
             'cflags': [
                 '<!@(<(pkg-config) --cflags libexif)',
             ],
             'defines': [
               'USE_SYSTEM_LIBEXIF',
             ],
           },
         }
       ],
     }],
   ]
 }