php: patch acinclude.m4 instead of aclocal.m4

aclocal.m4 gets regenerated from acinclude.m4, so patch the last.

Fixes "Extensions are not supported on this platform" error when
loading any external (zend) extension in php.ini.
Was caused by 0001-ditch-unset.patch not being applied to the
correct file, and our ac_cv_func_dlopen=yes env setting being unset.

Signed-off-by: Floris Bos <bos@je-eigen-domein.nl>
Signed-off-by: Peter Korsgaard <peter@korsgaard.com>