brew安裝sip時出現的問題：
$ brew install sip
Error: The `brew link` step did not complete successfully
The formula built, but is not symlinked into /usr/local
Could not symlink include/sip.h
/usr/local/include is not writable.
You can try again using:
brew link sip
$ brew link sip
Linking /usr/local/Cellar/sip/4.19.5...
Error: Could not symlink include/sip.h
/usr/local/include is not writable.發現/usr/local/下沒有路徑/usr/local/include
需要新建該路徑，並修改權限
解決：
$ sudo mkdir /usr/local/include
$ sudo chown $(whoami):admin /usr/local/include成功：
$ brew link sip
Linking /usr/local/Cellar/sip/4.19.5... 10 symlinks created
