Consequences of using MacPorts GCC as a fallback compiler on PowerPC

[Mojca Miklavec]

Dear Ryan,

I have no idea how to solve the issue with existing-possibly-broken
binaries (the problem with 10.5/PPC is that lots and lots of binaries
do not even build, so worrying about the few
built-but-new-to-be-broken binaries is not worrying me too much in
comparison). I admit it's a problem and that a number of ports would
need to be revbumped, but I have no clue how to figure out which ones.
Maybe Joshua has a recipe in his sleeve (he did some magic for
rev-upgrading after libc++ switch after all).

I admit that I forgot about the consequences of Ken's change that now
the flag -D_GLIBCXX_USE_CXX11_ABI=0 is missing when building those
binaries (to keep the compatibility in place), but I'm fully in favour
of either
(a) always adding -D_GLIBCXX_USE_CXX11_ABI=0 to CXXFLAGS (probably to
LDFLAGS as well?) when the compiler matches certain criteria
(b) or building libstdc++ in the way that will make this default
behaviour (I didn't even know this was possible)

I don't care too much which of the two options gets implemented. The
second one is probably easier to do.

Additional question for Ken: if we do (b) and keep using gcc6(?), do
we then even need any special (buildbot) setup for C++11 builds like
we plan to do for libc++-based builders?

Mojca