platforms /bin/sh gets one something uselessly broken.
Also, don't set MAKE to Solaris's make on Solaris; while this might be
necessary building standalone, in pkgsrc it's foolish.
Instead of extracting the runtime twice for src/ and base/ and then
haphazardly patching either or both copies, patch only one copy and
create the other *after* patching.
(better yet would be not to copy the thing at all, but I think there
are smlnj reasons you can't do that)
