diff -Naur -u a/configure.in b/configure.in
--- a/configure.in	2013-11-30 17:03:04.733971428 +0100
+++ b/configure.in	2013-11-30 17:03:21.231971410 +0100
@@ -205,7 +205,7 @@
   [ with_gui="no" ])
 AM_CONDITIONAL(WITH_GUI, [test "$with_gui" = "yes"])
 if test "$with_gui" = "yes"; then
-  PKG_CHECK_MODULES(GTKMM, gtkmm-2.4 >= 2.4)
+  PKG_CHECK_MODULES(GTKMM, gtkmm-2.4 >= 2.4 x11)
 dnl  PKG_CHECK_MODULES(GTHREAD, gthread-2.0 >= 2.0)
 dnl  GTKMM_LIBS="$GTKMM_LIBS $GTHREAD_LIBS"
   AC_SUBST(GTKMM_CFLAGS)