Merge r1597533, r1649491, r1665216, r1756553, r1756631, r1726675, r1718496, r1718476, r1747469 from trunk:

mod_cache: try to use the key of a possible open but stale cache entry
if we have one in cache_try_lock(). PR 50317

Submitted by: Ruediger Pluem


* modules/cache/mod_socache_memcache.c (socache_mc_store): Pass
  through expiration time.

Submitted by: Faidon Liambotis <paravoid debian.org>, jorton


* mod_cache: Preserve the Content-Type in case of 304 response.
304 does not contain Content-Type and mod_mime regenerates
the Content-Type based on the r->filename. This later leads to original
Content-Type to be lost (overwriten by whatever mod_mime generates).


mod_cache: Use the actual URI path and query-string for identifying the
cached entity (key), such that rewrites are taken into account when
running afterwards (CacheQuickHandler off).  PR 21935.
 


mod_cache: follow up to r1756553: log the real/actual cached URI (debug).



better s-maxage support
 
+  *) mod_cache: Consider Cache-Control: s-maxage in expiration
+     calculations.  [Eric Covener]
+
+  *) mod_cache: Allow caching of responses with an Expires header
+     in the past that also has Cache-Control: max-age or s-maxage.
+     PR55156. [Eric Covener]




remove dead code leftover from r1023387. 

Prior to this revision, there was an apr_atoi64 in this context.
Now, ap_cache_control() sets control.max_age (which is checked here) when
the maxage value was parsed OK.



duplicate debug-level AH00764 in the just-validated path.



Rename ap_casecmpstr[n]() to ap_cstr_casecmp[n](), update with APR doxygen
Submitted by: jkaluza, jorton, jkaluza, ylavic, ylavic, covener, covener, covener, wrowe
Reviewed/backported by: jim


git-svn-id: https://svn.apache.org/repos/asf/httpd/httpd/branches/2.4.x@1772331 13f79535-47bb-0310-9956-ffa450edef68

httpd compiles warning free on gcc and every new warning will be treated as an error, standard c-89 is enforced

http_config: follow up to r1702948: maybe unused, yet maybe usefull too.
Submitted by: icing, ylavic
Reviewed/backported by: jim


git-svn-id: https://svn.apache.org/repos/asf/httpd/httpd/branches/2.4.x@1772330 13f79535-47bb-0310-9956-ffa450edef68

git-svn-id: https://svn.apache.org/repos/asf/httpd/httpd/branches/2.4.x@1772252 13f79535-47bb-0310-9956-ffa450edef68

git-svn-id: https://svn.apache.org/repos/asf/httpd/httpd/branches/2.4.x@1772251 13f79535-47bb-0310-9956-ffa450edef68

git-svn-id: https://svn.apache.org/repos/asf/httpd/httpd/branches/2.4.x@1772126 13f79535-47bb-0310-9956-ffa450edef68

git-svn-id: https://svn.apache.org/repos/asf/httpd/httpd/branches/2.4.x@1771661 13f79535-47bb-0310-9956-ffa450edef68

git-svn-id: https://svn.apache.org/repos/asf/httpd/httpd/branches/2.4.x@1771659 13f79535-47bb-0310-9956-ffa450edef68

git-svn-id: https://svn.apache.org/repos/asf/httpd/httpd/branches/2.4.x@1771657 13f79535-47bb-0310-9956-ffa450edef68

git-svn-id: https://svn.apache.org/repos/asf/httpd/httpd/branches/2.4.x@1771596 13f79535-47bb-0310-9956-ffa450edef68

git-svn-id: https://svn.apache.org/repos/asf/httpd/httpd/branches/2.4.x@1771595 13f79535-47bb-0310-9956-ffa450edef68

mod_http2: new directive H2EarlyHints



git-svn-id: https://svn.apache.org/repos/asf/httpd/httpd/branches/2.4.x@1771018 13f79535-47bb-0310-9956-ffa450edef68

git-svn-id: https://svn.apache.org/repos/asf/httpd/httpd/branches/2.4.x@1771005 13f79535-47bb-0310-9956-ffa450edef68

mod_http2: PUSH triggers only on GET
mod_proxy_http2: 1xx responses not forwarded unconditionally on HTTP/1.x connections


git-svn-id: https://svn.apache.org/repos/asf/httpd/httpd/branches/2.4.x@1771000 13f79535-47bb-0310-9956-ffa450edef68

git-svn-id: https://svn.apache.org/repos/asf/httpd/httpd/branches/2.4.x@1770847 13f79535-47bb-0310-9956-ffa450edef68

git-svn-id: https://svn.apache.org/repos/asf/httpd/httpd/branches/2.4.x@1770839 13f79535-47bb-0310-9956-ffa450edef68

mod_ssl: Fix quick renegotiation (OptRenegotiaton) with no intermediate
in the client certificate chain.  PR 55786.

This is done by handling an empty cert chain as no/NULL chain.


Submitted by: ylavic
Reviewed/backported by: jim


git-svn-id: https://svn.apache.org/repos/asf/httpd/httpd/branches/2.4.x@1770838 13f79535-47bb-0310-9956-ffa450edef68

git-svn-id: https://svn.apache.org/repos/asf/httpd/httpd/branches/2.4.x@1770837 13f79535-47bb-0310-9956-ffa450edef68

git-svn-id: https://svn.apache.org/repos/asf/httpd/httpd/branches/2.4.x@1770836 13f79535-47bb-0310-9956-ffa450edef68

Was folded into Revision 1769595 ??



git-svn-id: https://svn.apache.org/repos/asf/httpd/httpd/branches/2.4.x@1770830 13f79535-47bb-0310-9956-ffa450edef68

git-svn-id: https://svn.apache.org/repos/asf/httpd/httpd/branches/2.4.x@1770829 13f79535-47bb-0310-9956-ffa450edef68

git-svn-id: https://svn.apache.org/repos/asf/httpd/httpd/branches/2.4.x@1770818 13f79535-47bb-0310-9956-ffa450edef68

git-svn-id: https://svn.apache.org/repos/asf/httpd/httpd/branches/2.4.x@1770777 13f79535-47bb-0310-9956-ffa450edef68

git-svn-id: https://svn.apache.org/repos/asf/httpd/httpd/branches/2.4.x@1770773 13f79535-47bb-0310-9956-ffa450edef68

Replace jim's proposal into smaller chunks that are IMHO easier to review.

The end result is the same, except for the CHANGES entry and one comment that I
added to r1770752 vs. the Bugzilla patch and that was missing in jim's patch.


git-svn-id: https://svn.apache.org/repos/asf/httpd/httpd/branches/2.4.x@1770769 13f79535-47bb-0310-9956-ffa450edef68

git-svn-id: https://svn.apache.org/repos/asf/httpd/httpd/branches/2.4.x@1770761 13f79535-47bb-0310-9956-ffa450edef68

git-svn-id: https://svn.apache.org/repos/asf/httpd/httpd/branches/2.4.x@1770760 13f79535-47bb-0310-9956-ffa450edef68

git-svn-id: https://svn.apache.org/repos/asf/httpd/httpd/branches/2.4.x@1770759 13f79535-47bb-0310-9956-ffa450edef68

CMake: use CMAKE_REQUIRED_INCLUDES to find APR macros

When using CMake with Visual Studio on Windows, invoking the
CHECK_SYMBOL_EXISTS macro with the full paths to the include files seems
to always result in failure.

Instead, use the documented CMAKE_REQUIRED_INCLUDES variable to set the
include directory, and pass only the headers' base names to
CHECK_SYMBOL_EXISTS.

CMake: use generator expressions to find output files

Multi-configuration generators, like Visual Studio, use a different
output directory (Debug, Release, etc.) for each configuration. To find
the output files reliably, switch to using generator expressions instead
of hardcoding the file paths for PDBs, export files, etc.

CMake: quote installation paths

Deal with installation paths with spaces in them (e.g. "C:\Program
Files") by quoting the arguments to perl and xcopy.
Submitted by: jchampion
Reviewed/backported by: jim


git-svn-id: https://svn.apache.org/repos/asf/httpd/httpd/branches/2.4.x@1770674 13f79535-47bb-0310-9956-ffa450edef68

ssl: clear the error queue before SSL_read/write/accept()

If other modules or libraries do not clear the OpenSSL error queue after
a failed operation, other code that relies on SSL_get_error() -- in
particular, code that deals with SSL_ERROR_WANT_READ/WRITE logic -- will
malfunction later on. To prevent this, explicitly clear the error queue
before calls like SSL_read/write/accept().

PR: 60223
Submitted by: Paul Spangler <paul.spangler ni.com>
Submitted by: jchampion
Reviewed/backported by: jim


git-svn-id: https://svn.apache.org/repos/asf/httpd/httpd/branches/2.4.x@1770673 13f79535-47bb-0310-9956-ffa450edef68

Avoid adding duplicate subequest filters, as they would not be stripped
properly during an ap_internal_fast_redirect.


Submitted by: covener
Reviewed/backported by: jim


git-svn-id: https://svn.apache.org/repos/asf/httpd/httpd/branches/2.4.x@1770672 13f79535-47bb-0310-9956-ffa450edef68

git-svn-id: https://svn.apache.org/repos/asf/httpd/httpd/branches/2.4.x@1770560 13f79535-47bb-0310-9956-ffa450edef68

git-svn-id: https://svn.apache.org/repos/asf/httpd/httpd/branches/2.4.x@1770508 13f79535-47bb-0310-9956-ffa450edef68

git-svn-id: https://svn.apache.org/repos/asf/httpd/httpd/branches/2.4.x@1770504 13f79535-47bb-0310-9956-ffa450edef68

git-svn-id: https://svn.apache.org/repos/asf/httpd/httpd/branches/2.4.x@1770503 13f79535-47bb-0310-9956-ffa450edef68

git-svn-id: https://svn.apache.org/repos/asf/httpd/httpd/branches/2.4.x@1770154 13f79535-47bb-0310-9956-ffa450edef68

Added a note in the mod_headers docs about Content-Type and setifempty

This note has been added as a follow up of a stack overflow post
(thanks to Michael Allan for the research):

http://stackoverflow.com/questions/29398123/apache-2-4-set-mime-type-of-file-without-extension

After a chat in #httpd-dev it seems that the issue boils down to how %{CONTENT_TYPE}
is evaluated in util_expr_eval.c (r->content_type) vs how setifempty is (only a check
of the response headers). This particular behavior might be a bug or feature,
but it is worth to alert our users.

Submitted by: elukey


git-svn-id: https://svn.apache.org/repos/asf/httpd/httpd/branches/2.4.x@1770153 13f79535-47bb-0310-9956-ffa450edef68

git-svn-id: https://svn.apache.org/repos/asf/httpd/httpd/branches/2.4.x@1770022 13f79535-47bb-0310-9956-ffa450edef68

This commit also revert my last one about H2PushResource.
After a chat on #http-dev we decided to make it public since
it holds a Compatibility section.



git-svn-id: https://svn.apache.org/repos/asf/httpd/httpd/branches/2.4.x@1769853 13f79535-47bb-0310-9956-ffa450edef68

The directive will be available only from 2.4.24 onwards,
reverting to avoid confusing users.



git-svn-id: https://svn.apache.org/repos/asf/httpd/httpd/branches/2.4.x@1769791 13f79535-47bb-0310-9956-ffa450edef68

git-svn-id: https://svn.apache.org/repos/asf/httpd/httpd/branches/2.4.x@1769786 13f79535-47bb-0310-9956-ffa450edef68