gnu: emacs-php-mode: Fix installation prefix.

* gnu/packages/emacs-xyz.scm (emacs-php-mode)
[include]: Remove argument.
[phases]{add-lisp-dir-to-emacs-load-path}: Remove phase.
{enter-source-directory}: Add phase.

gnu/packages/emacs-xyz.scm

@@ -12486,13 +12486,11 @@ using Imenu, and Compilation mode support for MSBuild, devenv and xbuild.")
         (base32 "0bs9q62bd7885c39v7x1qz3w1fhpmpdgm72xwsk2yygw0ii425nn"))))
     (build-system emacs-build-system)
     (arguments
-     `(#:include (cons "^lisp/" %default-include)
-       #:phases
+     `(#:phases
        (modify-phases %standard-phases
-         (add-after 'add-source-to-load-path 'add-lisp-dir-to-emacs-load-path
+         (add-after 'unpack 'enter-source-directory
            (lambda _
-             (setenv "EMACSLOADPATH"
-                     (string-append (getcwd) "/lisp:" (getenv "EMACSLOADPATH"))))))))
+             (chdir "lisp"))))))
     (propagated-inputs `(("emacs-projectile" ,emacs-projectile)))
     (home-page "https://github.com/ejmr/php-mode")
     (synopsis "Major mode for editing PHP code")