[glib] Build with old libmount too

[Colin Walters <walters src gnome org>]

commit 96ebcee8c4d555805e6aa6cf5ea6fcb16299dc81
Author: Colin Walters <walters verbum org>
Date:   Wed Nov 1 10:21:34 2017 -0400

    Build with old libmount too
    
    Downstream: https://bugzilla.redhat.com/show_bug.cgi?id=1508056
    
    This is an easy change, and lets us build with RHEL7's libmount.
    
    See also https://github.com/ostreedev/ostree/commit/cee57a0268334d51cd312c6cdcf367bedfd3e30d

 configure.ac      |    6 ++++--
 gio/gunixmounts.c |    4 ++--
 2 files changed, 6 insertions(+), 4 deletions(-)
---
diff --git a/configure.ac b/configure.ac
index b34ec4d..e2eee28 100644
--- a/configure.ac
+++ b/configure.ac
@@ -1760,8 +1760,10 @@ 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])
+  # We used to check for mnt_unref_table(), but now for compat with
+  # e.g. RHEL7 just use mnt_free_table().  Let's keep this check
+  # anyways.
+  AC_CHECK_LIB([mount], [mnt_free_table], [:], [have_libmount=no])
   LIBS=$glib_save_LIBS
 
   if test $have_libmount != no; then
diff --git a/gio/gunixmounts.c b/gio/gunixmounts.c
index ef7899d..a3c40f5 100644
--- a/gio/gunixmounts.c
+++ b/gio/gunixmounts.c
@@ -505,7 +505,7 @@ _g_get_unix_mounts (void)
   mnt_free_iter (iter);
 
  out:
-  mnt_unref_table (table);
+  mnt_free_table (table);
 
   return g_list_reverse (return_list);
 }
@@ -1029,7 +1029,7 @@ _g_get_unix_mount_points (void)
   mnt_free_iter (iter);
 
  out:
-  mnt_unref_table (table);
+  mnt_free_table (table);
 
   return g_list_reverse (return_list);
 }