fuselib: patch to check for NULL in fuse_parse_cmdline()

[Helg Bredow]

Arguments to fuse_parse_cmdline() are not checked for NULL before assignment. 
This patch performs the check.

Index: fuse.c
===================================================================
RCS file: /cvs/src/lib/libfuse/fuse.c,v
retrieving revision 1.30
diff -u -p -u -p -r1.30 fuse.c
--- fuse.c      24 Oct 2017 09:01:05 -0000      1.30
+++ fuse.c      24 Oct 2017 13:12:51 -0000
@@ -426,10 +426,14 @@ fuse_parse_cmdline(struct fuse_args *arg
                return (-1);
        }
 
-       *mp = strdup(opt.mp);
-       if (*mp == NULL)
-               return (-1);
-       *mt = 0;
+       if (mp != NULL) {
+               *mp = strdup(opt.mp);
+               if (*mp == NULL)
+                       return (-1);
+       }
+
+       if (mt != NULL)
+               *mt = 0;
 
        return (0);
 }