(set-language-environment): On MS-DOS

(set-language-environment): On MS-DOS
terminals, install DOS-specific nonascii-translation-table if the
language info doesn't specify one.  Pass the default eol-type to
set-language-environment-coding-systems.
(set-default-coding-systems): Copy the eol-type property for the
new default values of {buffer-file,process}-coding-system from the
old defaults.
(set-language-environment-coding-systems): Accept an optional
argument EOL-TYPE, and set the eol-type property of the default
coding systems accordingly.
(set-terminal-coding-system): Enable menu item on MS-DOS terminals.
(set-keyboard-coding-system): Likewise.
(set-default-coding-systems): Don't set
default-terminal-coding-system on MS-DOS to anything but nil.
(prefer-coding-system): Describe in the doc string that
default-terminal-coding-system is not changed on MS-DOS.
(set-language-environment): For MS-DOS, set standard syntax table
and display table for all characters with code above 127.
(standard-display-european-internal): For MS-DOS, pass all
characters with code above 127 directly to the terminal, and don't
remap characters 160 and 146 in the unibyte case.