du: avoid abort on systems for which ->me_type is not malloc'd

On some systems (notably, BSD-based, like at least OpenBSD 4.9),
the me_type member does not come from the heap.
* src/du.c (fill_mount_table): Free the ->me_type member only
when it was malloc'd, i.e., when ->me_type_malloced is nonzero.
Bug introduced via commit v8.19-2-gcf7e1b5.
Reported as http://bugs.gnu.org/12542.

1 files changed, 2 insertions, 1 deletions

diff --git a/src/du.c b/src/du.c
index ee90da9ba..63daaa928 100644
--- a/src/du.c
+++ b/src/du.c
@@ -660,7 +660,8 @@ fill_mount_table (void)
 
       free (mnt_free->me_devname);
       free (mnt_free->me_mountdir);
-      free (mnt_free->me_type);
+      if (mnt_free->me_type_malloced)
+        free (mnt_free->me_type);
       free (mnt_free);
     }
 }