(find-coding-systems-region-subset-p): This function deleted.

(find-coding-systems-region-subset-p): This function deleted.
(sort-coding-systems-predicate): New variable.
(sort-coding-systems): New function.
(find-coding-systems-region): Use
find-coding-systems-region-internal.
(find-coding-systems-string): Use find-coding-systems-region.
(find-coding-systems-for-charsets): Check
char-coding-system-table.
(select-safe-coding-system-accept-default-p): New variable.
(select-safe-coding-system): Mostly rewritten.  New argument
ACCEPT-DEFAULT-P.
(select-message-coding-system): Call select-safe-coding-system
with ACCEPT-DEFAULT-P arg.
(reset-language-environment): Reset default-sendmail-coding-system
to the default value iso-latin-1.
(set-language-environment): Don't set the obsolete variable
charset-origin-alist.