php 无法加载 mcrypt.so 的解决方案

PHP Warning:  PHP Startup: Unable to load dynamic library '/usr/local/opt/php56-mcrypt/mcrypt.so' - dlopen(/usr/local/opt/php56-mcrypt/mcrypt.so, 9): Library not loaded: /usr/local/opt/libtool/lib/libltdl.7.dylib
  Referenced from: /usr/local/opt/php56-mcrypt/mcrypt.so
  Reason: image not found in Unknown on line 0

解决方案

brew install libtool