finch: find tcl/tk on Xcode-only
mighttpd2 3.2.0 (new formula)

This adds [mighttpd2][], a high-performance HTTP server for static files and CGI
scripts, written in Haskell.

[mighttpd2]: http://mew.org/~kazu/proj/mighttpd/en/
mighttpd2: add 3.2.0 bottle.

Closes #31835.

Signed-off-by: Misty De Meo <mistydemeo@gmail.com>