altivec for boinc-setiathome-enhanced on powerpc?

[b. f.]

> despite the --disable-altivec configure option in the Makefile of
> astro/boinc-setiathome-ennhanced (which should be removed because it is
> autodetected), it is enabled automatically for PowerPC but there it
> fails with cc1plus not recognizing the -faltivec option:
>
> http://pointyhat.freebsd.org/errorlogs/powerpc-errorlogs/e.9.20111009030040/boinc-setiathome-enhanced-6.12_1.log
>
> Does this mean we have no Altivec support or is something else going wrong?

"-faltivec" is only recognized by certain compilers, like Apple's
modified version of gcc.  You can try patching the port to use
"-maltivec -mabi=altivec" instead.  We don't want the presence of such
CPU extensions to be auto-detected by default, because then default
packages that are built on altivec-capable machines may fail on
machines that have the same ARCH, but either do not support altivec,
or have had their altivec support  disabled.  Instead, the
auto-detection should be turned on if !empty(MACHINE_CPU:Maltivec).
This is a little awkward, because the powerpc developers didn't add
code to src/share/mk/bsd.cpu.mk to automatically add altivec to the
MACHINE_CPU of certain variants of powerpc, as was done, for example,
with mmx and certain families of Intel and AMD processors.  But the
users can always add it themselves, in an included Makefile, like
make.conf.

b.