Should also compile with PHP Session extension disabled

[doaxrel]

When PHP is compiled with --disable-session, snuffleupagus fails to build. I have implemented a crude workaround (which gets the job done), but I suppose this should be implemented properly:

    && cd snuffleupagus-*/src \
    && sed -i 's;#include "ext/session/;//;g' php_*.h \
    && echo 'void hook_session() {}' > sp_session.c \

Tested on PHP 7.4.1 and snuffleupagus 0.11.