Semi-obsolete way to toggle display of ISO 8859 European characters.
This function is semi-obsolete; you probably don't need it, or else you
probably should use `set-language-environment' or `set-locale-environment'.
This function enables European character display if ARG is positive,
disables it if negative. Otherwise, it toggles European character display.
When this mode is enabled, characters in the range of 160 to 255
display not as octal escapes, but as accented characters. Codes 146
and 160 display as apostrophe and space, even though they are not the
ASCII codes for apostrophe and space.
Enabling European character display with this command noninteractively
from Lisp code also selects Latin-1 as the language environment.
This provides increased compatibility for users who call this function
in `.emacs'.