[gnome-remote-desktop] build: Build project with -D_GNU_SOURCE

[Jonas Ådahl <jadahl src gnome org>]

commit 0fea0a243215481c6067a44050406f7f3e8616f7
Author: Pascal Nowack <Pascal Nowack gmx de>
Date:   Sun Sep 27 12:20:23 2020 +0200

    build: Build project with -D_GNU_SOURCE
    
    In order to be able to access the program_invocation_name, g-r-d needs
    to be compiled with -D_GNU_SOURCE to have this variable available.

 meson.build | 2 ++
 1 file changed, 2 insertions(+)
---
diff --git a/meson.build b/meson.build
index abef01d..ab6da0d 100644
--- a/meson.build
+++ b/meson.build
@@ -26,6 +26,8 @@ if not have_rdp and not have_vnc
 endif
 
 if have_rdp
+  add_global_arguments('-D_GNU_SOURCE', language : 'c')
+
   freerdp_dep = dependency('freerdp2', version: freerdp_req)
   freerdp_client_dep = dependency('freerdp-client2', version: freerdp_req)
   freerdp_server_dep = dependency('freerdp-server2', version: freerdp_req)