Cross compile webrtc for ios on mac os.

甜思思

　　编译步骤
　　下载depot_tools
　　svn co http://src.chromium.org/svn/trunk/tools/depot_tools
　　设置PATH变量
　　export PATH=$PATH:`pwd`/depot_tools
　　设置代码路径
　　gclient config http://webrtc.googlecode.com/svn/trunk
　　设置项目组织方式为xcode
　　export GYP_GENERATORS="xcode"
　　开始同步代码
　　gclient sync --nohooks
　　gclient runhook --force
　　生成支持ios的项目文件
　　./build/gyp_chromium --depth=.  -DOS=ios -Dtarget_arch=arm -Dinclude_tests=0 -Denable_protobuf=0 -Denable_video=1 webrtc/webrtc.gyp
　　
　　gclient runhook 后遇到的问题
　　bogon:trunk probestar$ ./build/gyp_chromium --depth=. -DOS=ios -Dtarget_arch=arm -Dinclude_tests=0 -Denable_protobuf=0 -Denable_video=1 webrtc/webrtc.gyp
Updating projects from gyp files...
Traceback (most recent call last):
File "./build/gyp_chromium", line 161, in <module>
sys.exit(gyp.main(args))
File "/Users/probestar/Documents/WorkSpace/webrtc/trunk/tools/gyp/pylib/gyp/__init__.py", line 527, in main
return gyp_main(args)
File "/Users/probestar/Documents/WorkSpace/webrtc/trunk/tools/gyp/pylib/gyp/__init__.py", line 512, in gyp_main
generator.GenerateOutput(flat_list, targets, data, params)
File "/Users/probestar/Documents/WorkSpace/webrtc/trunk/tools/gyp/pylib/gyp/generator/ninja.py", line 2133, in GenerateOutput
pool.map(CallGenerateOutputForConfig, arglists)
File "/System/Library/Frameworks/Python.framework/Versions/2.7/lib/python2.7/multiprocessing/pool.py", line 225, in map
return self.map_async(func, iterable, chunksize).get()
File "/System/Library/Frameworks/Python.framework/Versions/2.7/lib/python2.7/multiprocessing/pool.py", line 522, in get
raise self._value
AssertionError: Multiple codesigning identities for identity: iPhone Developer
　　多个iPhone Developer证书，在Mac OS中的钥匙串中删除多余的证书即可。
　　报错
　　Traceback (most recent call last):
File "trunk/build/gyp_chromium", line 148, in <module>
not 'OS=ios' in os.environ.get('GYP_DEFINES'):
TypeError: argument of type 'NoneType' is not iterable
Error: Command /usr/bin/python trunk/build/gyp_chromium --depth=trunk trunk/all.gyp -Dextra_gyp_flag=0 returned non-zero exit status 1 in /Users/probestar/Documents/WorkSpace/webrtc
　　没有做环境配置
　　export GYP_DEFINES="$GYP_DEFINES OS=ios target_arch=armv7"
export GYP_GENERATOR_FLAGS="$GYP_GENERATOR_FLAGS output_dir=out_ios"
export GYP_CROSSCOMPILE=1
cd trunk
export GYP_DEFINES="build_with_libjingle=1 build_with_chromium=0 libjingle_objc=1"
export GYP_GENERATORS="xcode"
　　gclient runhook -- force
　　没有生成项目文件
　　缺少环境配置，默认生成ninja的项目
　　export GYP_GENERATORS="xcode"
　　gclient runhook 阶段报错
　　Updating projects from gyp files...
gyp: trunk/third_party/libsrtp/libsrtp.gyp not found (cwd: /Users/probestar/Documents/WorkSpace/webrtc)
Error: Command /usr/bin/python trunk/build/gyp_chromium --depth=trunk trunk/all.gyp -Dextra_gyp_flag=0 returned non-zero exit status 1 in /Users/probestar/Documents/WorkSpace/webrtc
　　缺少文件，删除.gclient中的target_os一行，重新gclient sync即可