Add (require 'flymake-proc)

[takeokunn]

The following changes have been commited to the Emacs master branch.
emacs-mirror/emacs@81c6569

The places where flymake-proc is used within php-mode are as follows.

$ git grep "flymake-proc".lisp/php-flymake.el: (setq-local flymake-proc-allowed-file-name-masks nil)lisp/php-mode.el: (unless (boundp 'flymake-proc-allowed-file-name-masks) $

7e93315 I added (require 'flymake-proc) in this commit.

[zonuexe]

@takeokunn Thank you!