use WARNS?=4 for all Lua modules

turn on warnings, and fix compilation issues.

Makefile to build gpio.so.

lua: updated from 5.1 to 5.3 work3

* lua(1):
- changed lua_Integer to intmax_t
- updated distrib/sets/lists and etc/mtree
- updated bsd.lua.mk
- fixed bozohttpd (lua-bozo.c)
- compatibilized bindings: gpio, sqlite
* lua(4):
- removed floating-point and libc dependencies using '#ifndef _KERNEL'
- fixed division by zero and exponentiation
- libkern: added isalnum(), iscntrl(), isgraph(), isprint() and ispunct()
- acpica: removed isprint() from acnetbsd.h
- libc: moved strcspn.c, strpbrk.c and strspn.c to common
- removed stub headers
- compatibilized bindings: luapmf, luasystm
* reorganized luaconf.h
* updated doc/CHANGES and doc/RESPONSIBLE

branches: 1.8.2;
also register gpio_methods on the gpio table

branches: 1.7.2;
Add __printflike attribution to use vprintf and friends with an argument
as format string.

Remove an unused constant.

Remove software pulsing.

Start numbering pions with 0, not 1. Ruined a demo, so it was a bad idea.

branches: 1.3.2;
turn on warnings, and fix compilation issues.

Add NetBSD CVS marker, remove some whitespace.

Interface gpio(4) from Lua. Not linked to the build.