* Don't fiddle with NDEBUG in C code
It is way to late to do this in php.h, since assert.h has already been
included. Even pushing that down to zend_portability.h may not have
the desired effect. Instead we define or undefine NDEBUG as CFLAG, so
that it works in all circumstances.
As a last resort we fail at build time, if `NDEBUG` is defined when
`ZEND_DEBUG` is enabled.
We also remove the useless workaround in zend_test to include assert.h
again, since that usually won't have any effect anyway.
Co-authored-by: Arnaud Le Blanc <arnaud.lb@gmail.com>