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.
Add two makefiles to manage compiling packages with NetBSD libc.
* minix.libc.mk contains the proper CFLAGS/LDFLAGS
* pkgsrchooks.mk contains the logic for setting the flags.
* update bmake
Several pkg-config files were added to help pkgsrc learn about
the c, minlib, and compat_minix libraries.
