64 bit MACHINE_ARCH on solaris vs. pkg_install

[Tim Zingelman <tez%netbsd.org@localhost>]

On solaris 'uname -p' reports a 32 bit processor (sparc or i386) even
when the actual CPU is 64 bit capable (sparc64 or x86_64)

As a result, bootstrapping with --abi=64 is not enough to get pkgsrc
into a 64 bit frame of mind.

Adding MACHINE_ARCH=x86_64 (for instance) to mk.conf is a partial fix,
but with DESTDIR results in not being able to install anything, due to
packages being tagged as x86_64 but pkg_install thinking the current
system is i386.  It seems like pkgsrc needs some ugly exception code
for solaris?  or is there something I am missing?  should we wrap
uname to check mk.conf and provide the 64 bit answers if appropriate?

I also understand that some people report needing to set:
  MACHINE_GNU_PLATFORM=   sparc64-sun-solaris2
  SPARC_TARGET_ARCH=      sparcv9
as well (http://gnats.netbsd.org/44735 has lots of interesting work)

Thanks,

 - Tim