[gtk+/gtk-3-16] configure: specify that mir backend needs gio-unix

[Lars Uebernickel <larsu src gnome org>]

commit ae8fe51669790caf77b8975492efd5776fb27761
Author: Daniel van Vugt <daniel van vugt canonical com>
Date:   Wed Apr 15 13:19:14 2015 +0200

    configure: specify that mir backend needs gio-unix

 configure.ac |    1 +
 1 files changed, 1 insertions(+), 0 deletions(-)
---
diff --git a/configure.ac b/configure.ac
index 4a5f634..3f1f8a8 100644
--- a/configure.ac
+++ b/configure.ac
@@ -474,6 +474,7 @@ if test "$enable_mir_backend" = "yes"; then
   GDK_WINDOWING="$GDK_WINDOWING
 #define GDK_WINDOWING_MIR"
   MIR_PACKAGES="$MIR_DEPENDENCIES"
+  have_gio_unix=yes
 
   AM_CONDITIONAL(USE_MIR, true)
 else