Afterglow Ports Adjustments

[MingcongBai]

• Add m68k definitions.
• alpha: tune for EV67 (AlphaStation DS10).

[MingcongBai]

Okay, one moment...

• Gentoo and T2SDE seems to not specify -march=68020 and specifying this and -msoft-float seems to break glibc build. We wanted a baseline on 68020, however - more investigation needed.
• Gentoo produces an -malign-int variant for their stage tarball which, according to GCC, "produces code that runs somewhat faster on processors with 32-bit busses at the expense of more memory" and that it is an ABI breaking flag that Gentoo refers to as "future-proof." I might try it out.
• There is also an -mtune=68020-60 flag that's worth trying out as well.

[MingcongBai]

Merging since we are undergoing bring-up with Afterglow and these fixes are all going to be thoroughly tested before packages hit the users.