requirements: move more to compat.

[MikeMcQuaid]

Also, while we're here:

• gpg: move to compat.
• lines_cop: check for more deprecated requirements.
• lines_cop: deprecate 'needs :openmp'

[DomT4]

I missed the perl bit here.

Noting that this isn't disagreement or looking for an argument, a commitment to using Homebrew's perl is a commitment to revision bumping practically everything that brew uses perl on every version bump to the perl formula even if it's a minor. Perl libraries get installed in lib/perl5/#{version} and lib/perl5/site_perl/#{version}, so you can see the issue.

Happens with the system perl too but obviously that's almost never updated.

[ilovezfs]

Where system perl works, we can use it.

[MikeMcQuaid]

This already happens where perl is the default_formula. These deprecations are to reduce the deviations between building from source and building/installing bottles.

[DomT4]

Where system perl works, we can use it.

Thanks, that's the clarification I was looking for.