rmlint: fix build on old systems, fix universal variant

[barracuda156]

Description

As per the title. Fix the build for Leopard and SL, fix universal variant, which otherwise is mishandled by SCons.
(gcc-4.2 still fails to build rmlint even when incompatible optional flag is removed, so blacklist it.)

Type(s)

• bugfix
• enhancement
• security fix

Tested on

macOS 10.6 PPC (10A190)
Xcode 3.2

macOS 10.5.8
Xcode 3.1.4

Verification

Have you

• followed our Commit Message Guidelines?
• squashed and minimized your commits?
• checked that there aren't other open pull requests for the same change?
• referenced existing tickets on Trac with full URL?
• checked your Portfile with port lint --nitpick?
• tried existing tests with sudo port test?
• tried a full install with sudo port -vst install?
• tested basic functionality of all binary files?

[macportsbot]

Notifying maintainers:
@herbygillot for port rmlint.

[barracuda156]

PR to the source: sahib/rmlint#573 (without universal part, obviously).

[barracuda156]

@herbygillot Thanks!

[herbygillot]

Thanks for looking into this @barracuda156