[gnome-settings-daemon/wip/timerfd] build: Define HAVE_TIMERFD if we have timerfd_create

[Iain Lane <iainl src gnome org>]

commit a2fb9129ac564a8af802002e7237dd05eca21320
Author: Iain Lane <iainl gnome org>
Date:   Tue Sep 18 08:23:30 2018 +0100

    build: Define HAVE_TIMERFD if we have timerfd_create
    
    If we have timerfd support we will use it to wake up at the appropriate
    time. There is a fallback non-timerfd path in which we wake up every
    second.
    
    The problem is that we had forgotten to ever check for timerfd support.
    Add a check to the build system which enables this if timerfd_create()
    exists.
    
    Closes: #77

 meson.build | 4 ++++
 1 file changed, 4 insertions(+)
---
diff --git a/meson.build b/meson.build
index 2fd30cbd..93fab26f 100644
--- a/meson.build
+++ b/meson.build
@@ -125,6 +125,10 @@ if enable_gudev
 endif
 config_h.set('HAVE_GUDEV', enable_gudev)
 
+if cc.has_function('timerfd_create')
+  config_h.set('HAVE_TIMERFD', 1)
+endif
+
 # Check for libwayland-client
 enable_wayland = get_option('wayland')
 if enable_wayland