[glib/wip/smcv/darwin-c-source] build: Opt-in to Darwin extensions

[Simon McVittie <smcv src gnome org>]

commit 4c12bce1f9191820249dda3ac60fe36c77e1119c
Author: Simon McVittie <smcv collabora com>
Date:   Mon Feb 21 16:45:48 2022 +0000

    build: Opt-in to Darwin extensions
    
    In particular, this might give us access to `st_mtim.tv_nsec`. We
    already opt-in to GNU and QNX extensions on a similar basis.
    
    Signed-off-by: Simon McVittie <smcv collabora com>

 meson.build | 4 ++++
 1 file changed, 4 insertions(+)
---
diff --git a/meson.build b/meson.build
index c79084ac4..41e6fdb0c 100644
--- a/meson.build
+++ b/meson.build
@@ -130,6 +130,10 @@ if host_system == 'qnx'
   add_project_arguments('-D_QNX_SOURCE', language: 'c')
 endif
 
+if host_system == 'darwin'
+  add_project_arguments('-D_DARWIN_C_SOURCE', language: 'c')
+endif
+
 # Disable strict aliasing;
 # see https://bugzilla.gnome.org/show_bug.cgi?id=791622
 if cc.has_argument('-fno-strict-aliasing')