As fcgi_request is an opaque struct as of PHP 7, expose a new API
function fcgi_end() which does fcgi_flush() with end=1 and checks/
sets the ->ended flag.
"closed" refers to whether FCGI_END_REQUEST has been sent, while
the "close" operation does something entirely different. It gets
extra confusing when fcgi_is_closed() does not actually return
fcgi_request.closed...
Previously fcgi_request defined in main/fastcgi.h might be treated differently in different files, because of different behavior of #ifdef TCP_NODELAY. This leaded to stack memory corruption and unpredictable crashes.