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

build/linux/unbundle/flac.gyp

Index: build/linux/unbundle/flac.gyp
diff --git a/build/linux/unbundle/opus.gyp b/build/linux/unbundle/flac.gyp
similarity index 51%
copy from build/linux/unbundle/opus.gyp
copy to build/linux/unbundle/flac.gyp
index e8c30ba1e425b10c39e859b521d68aee0c8a05dc..9e4a6643951568b0bba1f447610b732bf993d7c5 100644
--- a/build/linux/unbundle/opus.gyp
+++ b/build/linux/unbundle/flac.gyp
@@ -5,21 +5,20 @@
 {
   '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': [
@@ -27,10 +26,10 @@
       ],
       '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)',
         ],
       },
     },