Add a gyp target for producing a voice engine merged library.

This is based on webrtc/build/merge_libs.gyp, with a dependency on
voice_engine.gyp instead and suitable name changes.

Executing:
$ rm -rf out/
$ ./webrtc/build/gyp_webrtc -Denable_video=0 -Denable_protobuf=0
-Drelease_optimize=s webrtc/build/merge_libs_voice.gyp
$ ninja -C out/Release merged_lib_voice

results in a minimially sized voice engine lib at:
out/Release/librtc_voice_merged.a

Linux: 6.4 MB
Mac: 3.7 MB

R=braveyao@webrtc.org

Review URL: https://webrtc-codereview.appspot.com/23659004

git-svn-id: http://webrtc.googlecode.com/svn/trunk@7199 4adac7df-926f-26a2-2b94-8c16560cd09d

webrtc/build/merge_libs.gyp

@@ -10,9 +10,6 @@
   'includes': ['common.gypi',],
   'variables': {
     'merge_libs_dependencies': [
-      '../webrtc.gyp:webrtc',
-      '../sound/sound.gyp:rtc_sound',
-      '../libjingle/xmllite/xmllite.gyp:rtc_xmllite',
     ],
   },
   'targets': [
@@ -21,6 +18,9 @@
       'type': 'executable',
       'dependencies': [
         '<@(merge_libs_dependencies)',
+        '../webrtc.gyp:webrtc',
+        '../sound/sound.gyp:rtc_sound',
+        '../libjingle/xmllite/xmllite.gyp:rtc_xmllite',
       ],
       'sources': ['no_op.cc',],
     },

webrtc/build/merge_libs_voice.gyp

@@ -0,0 +1,48 @@
+# Copyright (c) 2014 The WebRTC project authors. All Rights Reserved.
+#
+# Use of this source code is governed by a BSD-style license
+# that can be found in the LICENSE file in the root of the source
+# tree. An additional intellectual property rights grant can be found
+# in the file PATENTS.  All contributing project authors may
+# be found in the AUTHORS file in the root of the source tree.
+
+{
+  'includes': ['common.gypi',],
+  'variables': {
+    'merge_libs_dependencies': [
+    ],
+  },
+  'targets': [
+    {
+      'target_name': 'no_op_voice',
+      'type': 'executable',
+      'dependencies': [
+        '<@(merge_libs_dependencies)',
+        '../voice_engine/voice_engine.gyp:voice_engine'
+      ],
+      'sources': ['no_op.cc',],
+    },
+    {
+      'target_name': 'merged_lib_voice',
+      'type': 'none',
+      'dependencies': [
+        'no_op_voice',
+      ],
+      'actions': [
+        {
+          'variables': {
+            'output_lib_name': 'rtc_voice_merged',
+            'output_lib': '<(PRODUCT_DIR)/<(STATIC_LIB_PREFIX)<(output_lib_name)<(STATIC_LIB_SUFFIX)',
+          },
+          'action_name': 'merge_libs_voice',
+          'inputs': ['<(PRODUCT_DIR)/<(EXECUTABLE_PREFIX)no_op_voice<(EXECUTABLE_SUFFIX)'],
+          'outputs': ['<(output_lib)'],
+          'action': ['python',
+                     'merge_libs.py',
+                     '<(PRODUCT_DIR)',
+                     '<(output_lib)',],
+        },
+      ],
+    },
+  ],
+}