Minimal C program and Makefile used for testing Homebrew.

test-bot: fix summary

keg: make guile's site-dir persistent

test-bot: fix bottling non-testing jobs.

Need to handle when the `BOT_PARAMS` are `nil`.

test-bot: fix multiline regex.

bottle: remove debug statements.

test-bot: fix regex placement.

test-bot: handle more Jenkins configurations.

Fix Library/Homebrew/dev-cmd RuboCop warnings

Fix Library/Homebrew/utils RuboCop warnings

Fix Library/Homebrew/test RuboCop warnings

caveats: highlight PKG_CONFIG_PATH if exists

Things that install Guile scheme objects should be doing so in
HOMEBREW_PREFIX/share/guile/site, which should be persistent rather
than a symlink to any formulae's Cellar, not even guile's necessarily as
https://github.com/Homebrew/homebrew-core/commit/f061d864d99da4064a763ba51a37ecf3cff8943c
managed to expose.

I believe guile isn't actually configured correctly to expect
this directory, but since absolutely nobody has complained to
date as far as I can find & `gnutls` seems to be the only formula
using it this way the temptation is to leave it misconfigured
& use this directory for site schemes.

I don't really know the deeper issues around messing with Guile's
configuration so going for a minimal fix seems the safest option.

Used in trying to use a `Jenkinsfile`.