[MacPorts] #41782: Default to apple-gcc-4.2 on Tiger

[MacPorts]

#41782: Default to apple-gcc-4.2 on Tiger
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 Reporter:  ryandesign@…  |      Owner:  macports-tickets@…
     Type:  enhancement   |     Status:  new
 Priority:  Normal        |  Milestone:
Component:  base          |    Version:  2.2.99
 Keywords:  tiger         |       Port:
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 I propose we switch the default compiler on Tiger from gcc-4.0 to apple-
 gcc-4.2 because gcc-4.0 is old and has numerous problems. So few
 maintainers have access to Tiger anymore that when the few remaining Tiger
 users encounter these problems and file tickets, they don't get resolved.
 We can fix a lot of them, all at once, with this one simple change.

 We already switched the default compiler on Leopard from gcc-4.0 to
 gcc-4.2 in MacPorts 2.2. This was easy since Xcode 3 on Leopard comes with
 gcc-4.2. Xcode 2 on Tiger does not come with gcc-4.2, so we would have to
 use the apple-gcc42 port, which imposes an additional dependency on users,
 but this port does not change much anymore so it's a one-time build and a
 one-time inconvenience.

 In addition to fixing the types of gcc-4.0 problems that this switch fixed
 on Leopard, it will have two additional benefits on Tiger:

 1. It will let us switch our default configure.cppflags from
 `-I${prefix}/include` to `-isystem${prefix}/include` which will solve a
 whole set of build problems; see #40656. gcc-4.0 on Tiger has a bug that
 causes compile failures for C++ code if we make this change.
 2. It will fix undefined symbol errors when using an SDK (e.g. #25053)

 I plan to work on a patch for this and then test it on my Tiger machine by
 uninstalling and reinstalling my ports.

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Ticket URL: <https://trac.macports.org/ticket/41782>
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