Changes like these are expected to be included in the next version of mtools for VMS, which is expected to be version 3.9.10b.
Previously, mtools could fail with confusing error messages when a VMS file specification including a directory was used for an image file ("-i"). For example:
$ mtools -c mdir -i [-]FLOP.IMG :: *** Dummy fork() *** Pipe read error: no such file or directory
For some (unknown) reason, mtools attempts to do a UNIX-style wildcard expansion on the image file specification, and the method used fails on VMS. With this change, this wildcard expansion is not attempted on VMS.