Bug#2454: mount-2.5-5 hangs when type not specified

["Mark W. Eichin" <eichin@kitten.gen.ma.us>]

Here's the fix. Because of the block_signals (SIG_BLOCK) at line
482, the SEGV from strcasecmp(NULL,"auto") is blocked, and strcasecmp
spins (probably retrying at that address? not sure) with signals
blocked until you hit it with a kill -9. Please propagate this back to
the upstream maintainer. (Simply leaving *type == NULL is enough,
since that's equivalent to explicitly specifying "auto"...)

*** mount.c	1996/03/03 23:04:40	1.1
--- mount.c	1996/03/03 23:05:06
***************
*** 384,390 ****
  try_mount5 (char *spec, char *node, char **type, int flags, char *mount_opts) {
     char *fsname;

!    if (strcasecmp (*type, "auto") == 0)
        *type = NULL;

     if (!*type) {
--- 384,390 ----
  try_mount5 (char *spec, char *node, char **type, int flags, char *mount_opts) {
     char *fsname;

!    if (*type && strcasecmp (*type, "auto") == 0)
        *type = NULL;

     if (!*type) {