[gdm] Add missing dependency to .pc file

[Robert Ancell <rancell src gnome org>]

commit bfd35b85156feec154d46f5d476407e6dcd2f661
Author: Robert Ancell <robert ancell canonical com>
Date:   Tue Dec 5 14:10:43 2017 +1300

    Add missing dependency to .pc file

 libgdm/gdm.pc.in |    1 +
 1 files changed, 1 insertions(+), 0 deletions(-)
---
diff --git a/libgdm/gdm.pc.in b/libgdm/gdm.pc.in
index 9570d8c..65ee6d3 100644
--- a/libgdm/gdm.pc.in
+++ b/libgdm/gdm.pc.in
@@ -8,3 +8,4 @@ Description: Client Library for communicating with GDM daemon
 Version: @VERSION@
 Libs: -L${libdir} -lgdm
 Cflags: -I${includedir}/gdm
+Requires: gobject-2.0