temp-buffer-resize-mode

temp-buffer-resize-mode is a variable defined in `help.el'.
Its value is

nil

Documentation:
Non-nil if Temp-Buffer-Resize mode is enabled.
See the command `temp-buffer-resize-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 `temp-buffer-resize-mode'.

You can customize this variable.