Use GDK_WINDOWING_X11 to check for X backend support

Checking for gtkx.h does not work as intended, as this header is available
even if there's no X backend.

1 files changed, 1 insertions, 1 deletions

diff --git a/src/lib/eventloop.c b/src/lib/eventloop.c
index d3aef7e7..d7182339 100644
--- a/src/lib/eventloop.c
+++ b/src/lib/eventloop.c
@@ -181,7 +181,7 @@ GtkWidget *
 GNUNET_GTK_plug_me (const char *env_name,
                     GtkWidget *main_window)
 {
-#if HAVE_GTK_GTKX_H
+#if GDK_WINDOWING_X11
   const char *plugid;
   GtkWidget *plug;
   GtkWidget *child;