Install it under /usr/include

ones that are useful for all protocols, not just IPv6).

__null is a magic constant of integral type that converts to a null pointer
as should be, but warns for ambiguity when used to resolved an overload
between an integral type and a pointer type.

(this follows FreeBSD and Linux. Single Unix 2 is still illogical)

so that machine -> i386, and not the other way around,
or, for arches such as amiga/m68k, make amiga & m68k true directories
and let machine -> amiga.

link.h or dlfcn.h

Also make them prereq in the case of make includes

installation of includes can happen.  Do these before and not run via ${SUDO}.

really change the API since those parameters that was been constified
really are not modified by getcap(3) routines.

routines since they cannot read a hashed .db file from the old code.
Most of these files just have their RCS/SCCS tags standardized.
Note that mpool.3 has not been updated to reflect the new mpool interface.
o Add a real dbm(3) manpage

All POSIX libc api now there (to P1003.1c/D10)
(more md stuff is needed for other libc/arch/*)
(setlogin is no longer a special syscall)
Add -pthread option to gcc (that makes it use -lc_r and -D_POSIX_THREADS).
Doc some re-entrant routines
Add libc_r to intro(3)
dig() uses some libc srcs and an extra -I was needed there.
Add more md stuff to libc_r.
Update includes for the pthreads api
Update libc_r TODO