Include only needed header files per each source file

With help and OK from tb@

by popular request, stop giving away numeric letters. no more will the
appearance of 509 in a symbol name tell you what letter to guess first.

By popular demand, allow any ELF file to be passed to -d as a word list, in
which case its symbols will be used.
Which means that `hangman -k' is equivalent to `hangman -d /bsd' now.

ok beck@ tedu@

rcsid[] and sccsid[] and copyright[] are essentially unmaintained (and
unmaintainable). these days, people use source. these id's do not provide
any benefit, and do hurt the small install media
(the 33,000 line diff is essentially mechanical)
ok with the idea millert, ok dms

Add a -k option to use the kernel symbols as the words file.

Remove the advertising clause in the UCB license which Berkeley
rescinded 22 July 1999. Proofed by myself and Theo.

Merge NetBSD changes (use const where appropriate; allow alternate wordlists).
Add some code beyond that so the game doesn't hang if it gets a badly formatted
alternate wordlist.

tags, formatting, ANSI-fication, prototypes, de-typos, and the occasional
initialization, removal of unused variable, or other minor fix. Most
changes are from or inspired by NetBSD.

branches: 1.1.1;
Initial revision