(set-default-coding-systems):

(set-default-coding-systems):
Doc-string modified.
(prefer-coding-system): Likewise.  Call coding-system-base instead
of coding-system-parent.
(describe-language-environment): Print aliases of each coding
system.
(set-language-environment-hook): New variable.
(exit-language-environment-hook): New variable.
(set-language-environment): Call these hooks.  Before setting a
new language environment, exit from the
current-language-environment if necessary.
(input-method-verbose-flag): The value can be nil, t,
complex-only, or default.
(input-method-highlight-flag): Doc-string augmented.
(activate-input-method): Check if we can run the registered
function to activate an input method.