[glib] Check for a recent enough libmount

[Emmanuele Bassi <ebassi src gnome org>]

commit 5faaaac92cfdfe2fc40d79a5a7f420ba09beb03d
Author: Emmanuele Bassi <ebassi gnome org>
Date:   Sun May 14 20:33:00 2017 +0100

    Check for a recent enough libmount
    
    We need mnt_unref_table() in order to use libmount, but we also need to
    keep the fallback code for installations of libmount without a
    pkg-config file.
    
    https://bugzilla.gnome.org/show_bug.cgi?id=782628

 configure.ac |    3 +++
 1 files changed, 3 insertions(+), 0 deletions(-)
---
diff --git a/configure.ac b/configure.ac
index 5c57044..bd48088 100644
--- a/configure.ac
+++ b/configure.ac
@@ -1755,6 +1755,9 @@ PKG_CHECK_MODULES([LIBMOUNT], [mount >= 2.28], [have_libmount=yes], [have_libmou
 AS_IF([ test $have_libmount = maybe ], [
   glib_save_LIBS=$LIBS
   AC_CHECK_HEADER([libmount/libmount.h], [:], [have_libmount=no])
+
+  # Check for a recent enough libmount
+  AC_CHECK_LIB([mount], [mnt_unref_table], [:], [have_libmount=no])
   LIBS=$glib_save_LIBS
 
   if test $have_libmount != no; then