Fix "the-bug" (non-empty content in 304s) in PHP (patch by ezyang) and Apache
PHP should not produce any output, even if zlib.output_compression is
on, if the HTTP response code is 204 or 304 (no content or not modified).
Fixes PHP bug #42362 with php.cvs #56693, see:
http://bugs.php.net/bug.php?id=42362
http://news.php.net/php.cvs/56693
http://cvs.php.net/viewvc.cgi/php-src/ext/zlib/zlib.c?r1=1.183.2.6.2.5.2.9&r2=1.183.2.6.2.5.2.10
Apache should discard any body provided by a script (in any language, not
just PHP) when the status is "no content" or "not modified".
Addresses part of Apache bug #40953, see:
https://issues.apache.org/bugzilla/show_bug.cgi?id=40953#c7
Solves scripts.mit.edu support issue #773060, see:
https://help.mit.edu/Ticket/UpdateCallCenter.html?id=773060
https://diswww.mit.edu/charon/scripts/24018
