Fix cross-building.

Fix cross-building.

o  Move building libperl and miniperl from build-tools to
   cross-tools. libperl uses MACHINE_ARCH to determine the
   right configuration, which doesn't match the build
   machine when cross-building if they are built as build-
   tools.
o  Since miniperl needs to be built as a cross-tool, it
   needs to be installed under /usr/obj so that it can be
   used (cross-tools have a special object directory to
   avoid build conflicts. As a downside, you can't easily
   run cross-tools from their object directory). Remove
   the install and distribute override targets. To avoid
   having miniperl installed by installworld, remove it
   from SUBDIR.
o  We can't pickup miniperl from the object directory but
   since it's installed, depend on PATH. This is save,
   because the makefiles are run with a known path.
o  Build libperl again as part of the library target. A
   _libperl variable existed, but it was never defined.
o  Add chmod to the list of saved tools, because perl
   conditionally uses it during install.

The bootstrap-tools and cross-tools targets are modified to
avoid building profiled and shared libraries. While here,
have these targets build static binaries instead of shared
binaries.

Approved by: markm