Change to recommanded m4/-style small files
Revert use of config.h

Revert
7162e8db74df3232e5df1f6e091069f2d5ee1414
088493d499a544bcb6e37f0fd59d10034837262f

And drop AC_CONFIG_HEADERS so that config goes though the command line.
No longer generating config.h, update .gitignore
Droped autoconf hacks caused by AC_CONFIG_HEADERS