Cache: ignore stale-if-error for 4xx and 5xx codes. Previously the stale-if-error extension of the Cache-Control upstream header triggered the return of a stale response for all error conditions that can be specified in the proxy_cache_use_stale directive. The list of these errors includes both network/timeout/format errors, as well as some HTTP codes like 503, 504, 403, 429 etc. The latter prevented a cache entry from being updated by a response with any of these HTTP codes during the stale-if-error period. Now stale-if-error only works for network/timeout/format errors and ignores the upstream HTTP code. The return of a stale response for certain HTTP codes is still possible using the proxy_cache_use_stale directive. This change also applies to the stale-while-revalidate extension of the Cache-Control header, which triggers stale-if-error if it is missing. Reported at http://mailman.nginx.org/pipermail/nginx/2020-July/059723.html.

# Copyright (C) Igor Sysoev
# Copyright (C) Nginx, Inc.


CFLAGS =	-q -O2 -tWM -w-8004 $(CPU_OPT)
PCREFLAGS =	-DHAVE_CONFIG_H -DPCRE_STATIC -DPOSIX_MALLOC_THRESHOLD=10 \
		-DSUPPORT_PCRE8 -DHAVE_MEMMOVE


pcre.lib:
	cd $(PCRE)

	bcc32 -c $(CFLAGS) -I. $(PCREFLAGS) pcre_*.c

	copy /y nul pcre.lst
	for %n in (*.obj) do @echo +%n ^^& >> pcre.lst
	echo + >> pcre.lst

	tlib pcre.lib @pcre.lst

pcre.h:
	cd $(PCRE)

	copy /y pcre.h.generic pcre.h
	copy /y config.h.generic config.h
	copy /y pcre_chartables.c.dist pcre_chartables.c