[gtkmm-documentation] Require the latest gtkmm and glibmm.

[Murray Cumming <murrayc src gnome org>]

commit 31998fa8695059028f853c38827bfc82fe992e83
Author: Murray Cumming <murrayc murrayc com>
Date:   Mon Nov 30 10:02:06 2015 +0100

    Require the latest gtkmm and glibmm.

 configure.ac |    4 ++--
 1 files changed, 2 insertions(+), 2 deletions(-)
---
diff --git a/configure.ac b/configure.ac
index 358862b..1249809 100644
--- a/configure.ac
+++ b/configure.ac
@@ -23,8 +23,8 @@ MM_AX_CXX_COMPILE_STDCXX_11([noext],[mandatory])
 AC_PATH_PROG([PERL], [perl], [perl])
 AC_PROG_SED
 
-PKG_CHECK_MODULES([GIOMM], [giomm-2.4 >= 2.45.40])
-PKG_CHECK_MODULES([GTKMM], [gtkmm-3.0 >= 3.17.50])
+PKG_CHECK_MODULES([GIOMM], [giomm-2.4 >= 2.47.3.1])
+PKG_CHECK_MODULES([GTKMM], [gtkmm-3.0 >= 3.19.3])
 MM_PKG_CONFIG_SUBST([GTHREAD_CFLAGS], [--cflags-only-other gthread-2.0])
 
 # glib-compile-resources and C compiler are needed to generate and compile