[gtksourceviewmm] Use gtksourceview-4 instead of gtksourceview-3.0.

[Murray Cumming <murrayc src gnome org>]

commit 47c1219a3575c50ca8fc771925b6c65cd4a87561
Author: Murray Cumming <murrayc murrayc com>
Date:   Mon Nov 14 11:44:13 2016 +0100

    Use gtksourceview-4 instead of gtksourceview-3.0.

 configure.ac |    2 +-
 1 files changed, 1 insertions(+), 1 deletions(-)
---
diff --git a/configure.ac b/configure.ac
index 8a91591..bcd6d0a 100644
--- a/configure.ac
+++ b/configure.ac
@@ -27,7 +27,7 @@ LT_INIT([win32-dll disable-static])
 AC_PROG_CXX
 MM_AX_CXX_COMPILE_STDCXX_11([noext],[mandatory])
 
-AC_SUBST([GTKSOURCEVIEWMM_MODULES], ['glibmm-2.4 >= 2.46.1 gtkmm-3.0 >= 3.18.0 gtksourceview-3.0 >= 3.18.0'])
+AC_SUBST([GTKSOURCEVIEWMM_MODULES], ['glibmm-2.4 >= 2.46.1 gtkmm-3.0 >= 3.18.0 gtksourceview-4 >= 3.99.0'])
 PKG_CHECK_MODULES([GTKSOURCEVIEWMM], [$GTKSOURCEVIEWMM_MODULES])
 
 MM_PKG_CONFIG_SUBST([GTHREAD_CFLAGS], [--cflags-only-other gthread-2.0])