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.
This library includes various random and minix-specific functions
included in the Minix libc. Most of them should be part of libsys,
and in general it would be nice to extinguish this library over
time.