meson: build with _ISOC11_SOURCE on OpenBSD

Mesa builds with -std=c99 but uses timespec_get() a c11 function.
Build with _ISOC11_SOURCE for c11 visibility when -std is specified.
On linux c11 visibility comes from defining _GNU_SOURCE.

Fixes: e3a8013de8c ("util/u_queue: add util_queue_fence_wait_timeout")
Signed-off-by: Jonathan Gray <jsg@jsg.id.au>
Reviewed-by: Eric Engestrom <eric@engestrom.ch>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/5630>

diff --git a/meson.build b/meson.build
index 2c3397d673ebbef6359b76a14ffc436817e1a7f5..661a01e82b42b88a98b11f2223e0c406e570621d 100644 (file)
--- a/meson.build
+++ b/meson.build
@@ -949,6 +949,8 @@ elif host_machine.system() == 'windows'
   else
     pre_args += ['-D__MSVCRT_VERSION__=0x0700']
   endif
+elif host_machine.system() == 'openbsd'
+  pre_args += '-D_ISOC11_SOURCE'
 endif
 
 # Check for generic C arguments