libposix: raw files to import an installable libposix project
* libposix/bootstrap: New script to import gnulib posix modules
and bootstrap configury so that the result is an installable
libposix.la.
* libposix/configure.ac: New file to configure the new libposix
subdirectory.
* libposix/Makefile.am: New file to delegate build duties to the
generated libposix/lib/Makefile at make time.
* libposix/lib/Makefile.am: New file to make sure `-version-info'
is passed to libtool at libposix.la link-time.