Toggle Visual-Line mode in all buffers.
With prefix ARG, enable Global-Visual-Line mode if ARG is positive;
otherwise, disable it. If called from Lisp, enable the mode if
ARG is omitted or nil.
Visual-Line mode is enabled in all buffers where
`turn-on-visual-line-mode' would do it.
See `visual-line-mode' for more information on Visual-Line mode.
Non-nil if Global-Visual-Line mode is enabled.
See the command `global-visual-line-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-visual-line-mode'.