[libxml++] Use glibmm-2.52 instead of glibmm-2.4.

[Murray Cumming <murrayc src gnome org>]

commit c19d0c606e0525832f16d2e34942725a6c6802f8
Author: Murray Cumming <murrayc murrayc com>
Date:   Mon Nov 14 11:09:48 2016 +0100

    Use glibmm-2.52 instead of glibmm-2.4.

 configure.ac |    6 +++---
 1 files changed, 3 insertions(+), 3 deletions(-)
---
diff --git a/configure.ac b/configure.ac
index 1686cdb..4cc3d97 100644
--- a/configure.ac
+++ b/configure.ac
@@ -35,7 +35,7 @@ MM_AX_CXX_COMPILE_STDCXX([11], [noext],[mandatory])
 LT_PREREQ([2.2.6])
 LT_INIT([dlopen win32-dll disable-static])
 
-AC_SUBST([LIBXMLXX_MODULES], ['libxml-2.0 >= 2.7.7 glibmm-2.4 >= 2.32.0'])
+AC_SUBST([LIBXMLXX_MODULES], ['libxml-2.0 >= 2.7.7 glibmm-2.52 >= 2.32.0'])
 PKG_CHECK_MODULES([LIBXMLXX], [$LIBXMLXX_MODULES])
 
 AC_LANG([C++])
@@ -44,8 +44,8 @@ LIBXMLXX_CXX_HAS_EXCEPTION_PTR
 
 MM_ARG_ENABLE_DOCUMENTATION
 MM_ARG_WITH_TAGFILE_DOC([libstdc++.tag], [mm-common-libstdc++])
-MM_ARG_WITH_TAGFILE_DOC([libsigc++-2.0.tag], [sigc++-2.0])
-MM_ARG_WITH_TAGFILE_DOC([glibmm-2.4.tag], [glibmm-2.4])
+MM_ARG_WITH_TAGFILE_DOC([libsigc++-3.0.tag], [sigc++-3.0])
+MM_ARG_WITH_TAGFILE_DOC([glibmm-2.52.tag], [glibmm-2.52])
 
 # Evaluate the --enable-warnings=level option.
 MM_ARG_ENABLE_WARNINGS([LIBXMLXX_WXXFLAGS],