Upstream: fixed proxy_no_cache when caching errors. Caching errors, notably intercepted errors and internally generated 502/504 errors, as well as handling of cache revalidation with 304, did not take into account u->conf->no_cache predicates configured. As a result, an error might be cached even if configuration explicitly says not to. Fix is to check u->conf->no_cache in these cases. To simplify usage in multiple places, checking u->conf->no_cache is now done in a separate function. As a minor optimization, u->conf->no_cache is only checked if u->cacheable is set. As a side effect, this change also fixes caching errors after proxy_cache_bypass. Also, during cache revalidation u->cacheable is now tested, so 304 responses which disable caching won't extend cacheability of stored responses. Additionally, when caching internally generated 502/504 errors u->cacheable is now explicitly updated from u->headers_in.no_cache and u->headers_in.expired, restoring the behaviour before 8041:0784ab86ad08 (1.23.0) when an error happens while reading the response headers. Reported by Kirill A. Korinsky, https://freenginx.org/pipermail/nginx/2024-April/000082.html

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


have=NGX_WIN32 . auto/have_headers

CORE_INCS="$WIN32_INCS"
CORE_DEPS="$WIN32_DEPS"
CORE_SRCS="$WIN32_SRCS $IOCP_SRCS"
OS_CONFIG="$WIN32_CONFIG"
NGX_ICONS="$NGX_WIN32_ICONS"
SELECT_SRCS=$WIN32_SELECT_SRCS
POLL_SRCS=$WIN32_POLL_SRCS

ngx_pic_opt=
ngx_binext=".exe"

case "$NGX_CC_NAME" in

    gcc)
        CORE_LIBS="$CORE_LIBS -ladvapi32 -lws2_32"
        MAIN_LINK="$MAIN_LINK -Wl,--export-all-symbols"
        MAIN_LINK="$MAIN_LINK -Wl,--out-implib=$NGX_OBJS/libnginx.a"
        MODULE_LINK="-shared -L $NGX_OBJS -lnginx"
    ;;

    *)
        CORE_LIBS="$CORE_LIBS advapi32.lib ws2_32.lib"
    ;;

esac

EVENT_MODULES="$EVENT_MODULES $IOCP_MODULE"
#EVENT_FOUND=YES

have=NGX_HAVE_INET6 . auto/have

have=NGX_HAVE_IOCP . auto/have