. speeds up mkdep (i.e. world builds) significantly
. have to keep minix /bin/sed for a while because previous
usr/etc/rc depends on it
. force mkdep to use /usr/bin/sed for speedup
1. ack, a.out, minix headers (moved to /usr/include.ack),
minix libc
2. gcc/clang, elf, netbsd headers (moved to /usr/include),
netbsd libc (moved to /usr/lib)
So this obsoletes the /usr/netbsd hierarchy.
No special invocation for netbsd libc necessary - it's always used
for gcc/clang.
