Enable dosbox as an alternative for Linux

In my hands, dosemu throws a lot of errors. Hopefully dosbox will work better

non-git version of dosemu complains about not finding /media/cdrom
all versions complain about "ERROR: unknown window sizes li=0 co=0, setting to 80x25"
the logs suggest that x86_64 linux could be an explanation for unsafe memory allocation.
dosbox emulates cpu so it might be a better option.