httpd will die if there's a parse error in the code. An example is a missing semi-colon. Here is what happens when its run inside GDB:

(gdb) run
Starting program: /www/bin/httpd -X
(no debugging symbols found)...(no debugging symbols found)...(no debugging symbols found)...
Program received signal SIGSEGV, Segmentation fault.
0x182dce05 in _zval_ptr_dtor () at zend_execute_API.c:102
102             return(ce->type != ZEND_INTERNAL_CLASS);