Using -h will show a summarized view of the options, functions and
macros. Using --help will open `man` with the longer contets,
which is more convenient to search and gives a little bit of
formatting.
This scheme is similar to what is done for git subcommands, e.g.
`git commit -h` and `git commit --help`.
Reviewed-by: Ian Romanick <ian.d.romanick@intel.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/34268>
Caio Oliveira
6901f74fbf