allow to use a read-only directory

[fachat]

... e.g. with an assign option to the directory path (see other issue about wildcard option)

[fachat]

you mean that the directory is mounted, but protected from changes?

[nils-eilers]

Do you really ask yourself how you meant it? ;-)

[fachat]

oops :-) Then it will be this - mount/assign a directory, but protect it from changes

[fachat]

This also applies to read only image files that contain another image file. E.g. a R/O D80 file that contains a D64 file that is mounted. The D64 should "inherit" the write-protection from the parent.