Leave PHP5 wrapping them as integers as this change could cause
incompatibilities.
Fixes issue https://github.com/swig/swig/issues/686 noted by Nishant
Gupta.
PHP5's C extension API has changed substantially so you need to use
-php7 to specify you want PHP7 compatible wrappers.
Fixes https://github.com/swig/swig/issues/571