[MacPorts] #64694: gcc/libgcc: update older systems prior to 10.6 to a newer gcc version?

[MacPorts]

#64694: gcc/libgcc: update older systems prior to 10.6 to a newer gcc version?
----------------------------+---------------------------
  Reporter:  barracuda156   |      Owner:  (none)
      Type:  request        |     Status:  new
  Priority:  Normal         |  Milestone:
 Component:  ports          |    Version:  2.7.1
Resolution:                 |   Keywords:  leopard tiger
      Port:  libgcc, gcc10  |
----------------------------+---------------------------

Comment (by barracuda156):

 Replying to [comment:8 cjones051073]:
 > I am not going to do the above myself, i do not have the time but more
 importantly no means to test on OSX10.5 or older. But hopefully if someone
 else is interested the above would give them a starting point to make the
 changes

 Thank you for guidelines!

 It looks that `gcc12` is building fine for PPC – I am building 12.1.0 now
 on 10.6.8 via Rosetta, `libgcc12` built successfully, `gcc12` in the
 process. If that succeeds, I am mostly sure 10.5.8 will work too (after
 all, Iain tests both `ppc` and `ppc64` on Darwin).
 Cosmetic changes in the portfile will be needed: make a default variant
 supporting `libcxx` conditional (until it is tested on PPC and confirmed
 to work), remove a ban for older systems and `gcc-4.2` (which leads to an
 error otherwise), specify `gcc10-bootstrap` as a dependency on PPC. (The
 latter gonna actually fail on Rosetta, but for most of users Leopard is
 the only concern.)

 So apparently everything gonna work, as it is working with `gcc11`, for
 three PPC configurations: 10.5.8 (ppc + ppc64), 10A190 (ppc) and 10.6.8
 (ppc via Rosetta).

 What I am yet to do is to fix `gcc7` port logic, so that the whole
 procedure does not leave `gcc7` broken.

-- 
Ticket URL: <https://trac.macports.org/ticket/64694#comment:10>
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