configure: generate a fully statically linked exec

Allow to create an executable with no external dynamic libraries, also the
ones from the system. This is somewhat dependent of the used C lib, for
example glibc has some internal dynamic libraries loaded by itself, but for
other ones like eglibc or dietlib, this would produce a true static linked
executable. This can be of interest for embebers or resource constraints
platforms, but the main reason for this is to allow to use a Javascript
file as Linux kernel 'init' on NodeOS.

Reviewed-By: Fedor Indutny <fedor@indutny.com>