[gnome-software] build: Define _XOPEN_SOURCE in order to expose symlink() in headers

[Philip Withnall <pwithnall src gnome org>]

commit 1caea0c8820012b9b6b89a9bfd1e9351a2332351
Author: Philip Withnall <withnall endlessm com>
Date:   Wed Aug 16 14:19:36 2017 +0100

    build: Define _XOPEN_SOURCE in order to expose symlink() in headers
    
    We need symlink() and PATH_MAX in various places, which both require the
    _XOPEN_SOURCE feature test macro. Define it.
    
    Signed-off-by: Philip Withnall <withnall endlessm com>

 meson.build |    3 +++
 1 files changed, 3 insertions(+), 0 deletions(-)
---
diff --git a/meson.build b/meson.build
index 473762f..806d34e 100644
--- a/meson.build
+++ b/meson.build
@@ -89,6 +89,9 @@ add_global_link_arguments(
   language: 'c'
 )
 
+# Needed for PATH_MAX and symlink()
+add_project_arguments('-D_XOPEN_SOURCE=500', language : 'c')
+
 appstream_glib = dependency('appstream-glib', version : '>= 0.7.0')
 gdk_pixbuf = dependency('gdk-pixbuf-2.0', version : '>= 2.31.5')
 gio_unix = dependency('gio-unix-2.0')