opencv ios 在mac上安装报错

subprocess.CalledProcessError: Command '['xcodebuild', 'BITCODE_GENERATION_MODE=bitcode', 'IPHONEOS_DEPLOYMENT_TARGET=9.0', 'ARCHS=armv7', '-sdk', 'iphoneos', '-configuration', 'Release', '-parallelizeTargets', '-jobs', '6', '-target', 'ALL_BUILD', 'build']' returned non-zero exit status 65.
 

大概率是系统中python指令不存在只有python3指令
可以这样解决

$ python3 -m venv .venv
$ source .venv/bin/activate
(.venv) $ python ../opencv/platforms/ios/build_framework.py ....

或者

```
ln -s /usr/local/bin/python3 /usr/local/bin/python