I have an amd64 system, currently with netbsd-3 i386 installed.  I
want to crossbuild amd64 installation sets so I can dual-boot in amd64
mode.

When building for each of the targets (i386 and amd64) do I need
separate tools directories, as in (hosted on i386):

  ./build.sh -u -U -m i386  -T /tools-for-i386-host-and-i386-target ...
  ./build.sh -u -U -m amd64 -T /tools-for-i386-host-and-amd64-target ...

Or do I just need separate tools directories for each of the host
platforms, as in (hosted on i386):

  ./build.sh -u -U -m i386  -T /tools-for-i386-host ...
  ./build.sh -u -U -m amd64 -T /tools-for-i386-host ...

I think I read the relevant portions of BUILDING, but didn't see it
mentioned.  I tried the second approach, and it seemed to rebuild the
compat tools, and not touch the <tooldir>/i386--netbsdelf directory.

  Alan