Or you could just use int.

Do you mean something like this ?
https://pagure.io/SSSD/sssd/blob/master/f/src/util/util_errors.h#_26

On the platform I was using (FreeBSD), sssd's configure detects errno_t okay (and defines HAVE_ERRNO_T in config.h). But after Python.h (from python3.6) is included, _POSIX_C_SOURCE is defined (to 200809). This turns off Annex K extensions (of which errno_t is a part) unless you specify you want them (by defining __STDC_WANT_LIB_EXT1__).

Thus most of the sssd code that references errno_t compiles fine, but src/python/pysss.c fails because it includes Python.h which sets a knob that disables the Annex K extensions. Maybe this is a header pollution bug in python - perhaps it should not export _POSIX_C_SOURCE to users of its public API header (Python.h).

But the result now is that if __STDC_WANT_LIB_EXT1__ is not defined, the following errors occur when building pysss.c :

In file included from src/python/pysss.c:27:
In file included from ./src/util/util.h:51:
./src/util/util_errors.h:130:26: error: unknown type name 'errno_t'

It seems to me that HAVE_ERRNO_T is not enough in config.h perhaps - it could also define __STDC_WANT_LIB_EXT1__.

Here is a patch to add __STDC_WANT_LIB_EXT1__ if errno_t is detected:

--- configure.ac.orig   2019-06-13 20:22:59 UTC
+++ configure.ac
@@ -45,6 +45,7 @@
 AC_CHECK_HEADERS(stdint.h dlfcn.h)
 AC_CONFIG_HEADER(config.h)

 AC_CHECK_TYPES([errno_t], [], [], [[#include <errno.h>]])
+AM_CONDITIONAL([HAVE_ERRNO_T], [test "$ac_cv_type_errno_t" = yes])

 m4_include([src/build_macros.m4])
 BUILD_WITH_SHARED_BUILD_DIR
--- Makefile.am.orig    2019-06-13 20:22:59 UTC
+++ Makefile.am
@@ -123,6 +123,9 @@
                  -fno-strict-aliasing \
                  -std=gnu99
 endif
+if HAVE_ERRNO_T
+    AM_CFLAGS += -D__STDC_WANT_LIB_EXT1__
+endif

 pkgconfig_DATA =

Just using int instead of errno_tis probably more portable and certainly simpler. But the above fixes the case where errno_t is detected at configure time, and the Python.h header pollution turns on portability feature settings (e.g., _POSIX_C_SOURCE) that could disable the definition of errno_t in system headers.

I admit I can't tell if using this extra -D__STDC_WANT_LIB_EXT1__. My C/POSIX/standards knowledge is just not that deep. I would be wary of clashing with some of the GNU extensions or such.

All in all, isn't it better to keep the patch in freebsd tree as a downstream patch?

Thank you for taking time to submit this request for SSSD. Unfortunately this issue was not given priority and the team lacks the capacity to work on it at this time.

Given that we are unable to fulfill this request I am closing the issue as wontfix.

If the issue still persist on recent SSSD you can request re-consideration of this decision by reopening this issue. Please provide additional technical details about its importance to you.

Thank you for understanding.

SSSD is moving from Pagure to Github. This means that new issues and pull requests
will be accepted only in SSSD's github repository.

This issue has been cloned to Github and is available here:
- https://github.com/SSSD/sssd/issues/4997

If you want to receive further updates on the issue, please navigate to the github issue
and click on subscribe button.

Thank you for understanding. We apologize for all inconvenience.