Add build/linux/unbundle files for projects in separate repos.

build/linux/unbundle/flac.gyp

 # Copyright 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': 'opus',
+      'target_name': 'libflac',
       'type': 'none',
-      'direct_dependent_settings': {
-        'cflags': [
-          '<!@(pkg-config --cflags opus)',
-        ],
-      },
       'variables': {
-        'headers_root_path': 'src/include',
+        'headers_root_path': 'include',
         'header_filenames': [
-          'opus_custom.h',
-          'opus_defines.h',
-          'opus_multistream.h',
-          'opus_types.h',
-          'opus.h',
+          'FLAC/callback.h',
+          'FLAC/metadata.h',
+          'FLAC/assert.h',
+          'FLAC/export.h',
+          'FLAC/format.h',
+          'FLAC/stream_decoder.h',
+          'FLAC/stream_encoder.h',
+          'FLAC/ordinals.h',
+          'FLAC/all.h',
         ],
       },
       'includes': [
         '../../build/shim_headers.gypi',
       ],
       'link_settings': {
         'ldflags': [
-          '<!@(pkg-config --libs-only-L --libs-only-other opus)',
+          '<!@(pkg-config --libs-only-L --libs-only-other flac)',
         ],
         'libraries': [
-          '<!@(pkg-config --libs-only-l opus)',
+          '<!@(pkg-config --libs-only-l flac)',
         ],
       },
     },
   ],
 }