CMDR-DOS: Timestamping on newly created directory only works on hostfs

[JimmyDansbo]

If an SD card image is mounted in the emulator and a directory is created with DOS"MD:SOMEDIR", it seems the timestamp is not written correctly, even when the emulator is started with -rtc
Following, DOS"$=L" will not show timestamp and filesize.

When the SD card image is mounted in linux, I can see that the timestamp of a directory created with DOS"MD:SOMEDIR" is 1980-01-01 01:00:00

The issue does not exist when using hostfs

[mooinglemur]

The current X16 DOS/FAT32 code does not have support for timestamps on directories. If the file already has a timestamp, it won't be touched, but this is also true for mtime on directories when files are created inside.

Adding such support would only be partial until there is code to ensure that directories also have their mtimes updated when their contents change.

I initially thought this would be a simple change but it's more complex than I expected to get it right. I'll have to get back to it when I have had time to study the FAT32 spec.