[glom/gtkmm4v4] configure.ac: tests: Use gdkmm-4.0, not gdkmm-3.0

[Murray Cumming <murrayc src gnome org>]

commit f49276998d82a4f611b4fbd34879a62a41e6ef3d
Author: Murray Cumming <murrayc murrayc com>
Date:   Sat Apr 15 21:31:39 2017 +0200

    configure.ac: tests: Use gdkmm-4.0, not gdkmm-3.0

 configure.ac |    2 +-
 1 files changed, 1 insertions(+), 1 deletions(-)
---
diff --git a/configure.ac b/configure.ac
index 3b1aa7c..02d51a9 100644
--- a/configure.ac
+++ b/configure.ac
@@ -201,7 +201,7 @@ AC_DEFINE_UNQUOTED([ISO_CODES_PREFIX], ["$ISO_CODES_PREFIX"],
                    [Define to the installation prefix of the iso-codes module.])
 
 # This is used in one test:
-PKG_CHECK_MODULES([GDKMM], [gdkmm-3.0 >= 3.4.0])
+PKG_CHECK_MODULES([GDKMM], [gdkmm-4.0 >= 3.4.0])
 
 # Allow use of mm-common macros for the warnings option and for installing developer documentation.
 MM_PREREQ([0.9.5])