With XCode 8, clock_gettime will be incorrectly detected as being
available regardless of what OS X version we're targetting because the
symbol is available in the .tbd library as a weak symbol.
See: https://github.com/Homebrew/homebrew-core/issues/3727#issue-170086273
It's only starting from macOS 10.12 that clock_gettime is actually
available, so we can unconditionally disable it when targetting older
versions. We cannot simply do AC_CHECK_FUNCS with -Wl,-no_weak_imports
because the autoconf check does its own prototype declaration that
doesn't trigger that compiler flag.
https://bugzilla.gnome.org/show_bug.cgi?id=772451
Reintroduced patches:
* Make sure that fail_if(1) actually fails
from commit 9f99d056a2
New patches due to updated libcheck (based on 0.9.14):
* Checks in m4/check-checks.m4 to cater for new dependencies
* Conditional compile-time compat POSIX fallbacks for libcheck
* Avoid relative paths for libcheck header files
* Make timer_create() usage depend on posix timers, not librt
* Rely on default AX_PTHREAD behavior to allow HAVE_PTHREAD to be used
when checking for types and functions (like clock_gettime())
* Avoid double declaration of clock_gettime() when availabe outside of
librt by making compat clock_gettime() declaration conditional
* check 0.9.9 renamed _fail_unless() and 0.9.12 later renamed it again
to _ck_assert_failed(), so ASSERT_{CRITICAL,WARNING}() now calls this
function
* Remove libcheck fallback infrastructure for malloc(), realloc(),
gettimeofday() and snprintf() since either they appear to be
available or they introduce even more dependencies.
The result is an embedded check in gstreamer that has been tested by
running check tests in core, -base, -good, -bad, -ugly and rtsp-server
on Linux, OSX and Windows.
Fixes https://bugzilla.gnome.org/show_bug.cgi?id=727826
Without using AC_INCLUDES_DEFAULT explicitly,
certain platforms will complain that the header
was found, but not usable by the compiler.
This happens for instance on Solaris where certain
headers are needed to pull in proper defines.
Also upgrade to newer autoconf syntax and use proper quoting.
https://bugzilla.gnome.org/show_bug.cgi?id=667293
This is how we do it in the other modules, and gets rid of the annoying
dirty status for common when doing git status (at least once you clean
out the old files from there).
