ap_log_error: Include ap_config_auto.h to define _GNU_SOURCE

[bkuhls]

gettid() needs _GNU_SOURCE defined which is provided by ap_config_auto.h

Fixes buildroot error:
http://autobuild.buildroot.net/results/2f6/2f6b7bbb4c97e4c91b3abd6bb205e237e57045fa//build-end.log

log.c: In function 'log_tid':
log.c:637:21: error: implicit declaration of function 'gettid'; did you mean 'getgid'? [-Wimplicit-function-declaration]
637 | pid_t tid = gettid();

[notroj]

What glibc version is used there?

[bkuhls]

afaics

GNU C Library (Buildroot) stable release version 2.39.

[notroj]

Thanks. I don't understand why this is necessary.

https://github.com/apache/httpd/blob/trunk/server/log.c#L52 -> #include "ap_config.h"
https://github.com/apache/httpd/blob/trunk/include/ap_config.h#L183 -> #include "ap_config_auto.h"

The ap_config_auto.h.in generated by autoheader should have:

/* Enable GNU extensions on systems that have them.  */
#ifndef _GNU_SOURCE
# undef _GNU_SOURCE
#endif

Which happens on my system (Fedora with autoconf 2.71) , and in the tarballs released at apache.org. So I would assume that something is special about the way you're running autoheader?

[notroj]

That can't be it, because your patch also assumes that ap_config_auto.h defines _GNU_SOURCE.
Moving the #include "ap_config.h" to the top of log.c looks correct/justifiable, but directly including ap_config_auto.h here is wrong/unnecessary.

I think there's something broken with this build environment due to the cross-build. You are not seeing "normal" CPPFLAGS from APR 1.x either, which on Linux should look like:

checking for APR... yes
  setting CPP to "gcc -E"
  setting CPPFLAGS to " -DLINUX -D_REENTRANT -D_GNU_SOURCE"

Instead you see only:

checking for APR... yes
  setting LDFLAGS to " "

[notroj]

I'm still guessing this is a defect of a cross-build environment which should be investigated and fixed properly rather than trying to tweak the headers, closing since no feedback but feel free to update/reopen.