After upgraded to 10.12 and xcode8.2, when updating php with homebrew, i got these errors:
/usr/local/bin/phpize: line 61: /usr/local/Library/ENV/4.3/sed: No such file or directory
one way of solution you can find here, https://github.com/Homebrew/homebrew-php/issues/3352
but, for me, follow this step i resolve it. just run:
Have fun with macOS!