Toggle Font-Lock mode in all buffers.
With prefix ARG, enable Global-Font-Lock mode if ARG is positive;
otherwise, disable it. If called from Lisp, enable the mode if
ARG is omitted or nil.
Font-Lock mode is enabled in all buffers where
`turn-on-font-lock-if-desired' would do it.
See `font-lock-mode' for more information on Font-Lock mode.
Non-nil if Global-Font-Lock mode is enabled.
See the command `global-font-lock-mode' for a description of this minor mode.
Setting this variable directly does not take effect;
either customize it (see the info node `Easy Customization')
or call the function `global-font-lock-mode'.