Package was not found in the pkg-config search path.

周末跑个以前的项目，原本好好的makefile报错，

Package opencv was not found in the pkg-config search path.

Perhaps you should add the directory containing `opencv.pc'

to the PKG_CONFIG_PATH environment variable

No package 'opencv' found

一顿查资料，最后brew doctor提示：

You have a non-Homebrew 'pkg-config' in your PATH:

/opt/local/bin/pkg-config

注意/opt/local/bin/， 这是mac-port的目录，上次忘了为什么装了个mac-port，导致pkg-config冲突

解决就很简单了；

echo $PATH 看下路径；  

vi ~/.bash_profile 查下确保/usr/local/bin/ 目录在/opt/local/bin之前即可。