(coding-system-post-read-conversion)

(coding-system-post-read-conversion)
(coding-system-pre-write-conversion)
(coding-system-translation-table-for-decode)
(coding-system-translation-table-for-encode): Get the right
properties.
(with-coding-priority): New macro.
(detect-coding-with-language-environment): Use it.
(coding-system-equal): Use coding-system-plist.