Bring Building section more up to date
Bring Building section more up to date

Now that we have a proper GNU configure script there is no such thing as
lightweight, and the respected environment variables are listed at the
end of `./configure --help`

Signed-off-by: Joachim Nilsson <583c295fd7602c168ad814279bbc3894ba65f5d6@gmail.com>

troglobit/finit,troglobit/finit