This patch changes the noux build rules to produce a tar archive in
'bin/', alleviating the need for this step from the run scripts.
This way, the visible result of a built noux package is a single (tar)
file in '<build-dir>bin/', which is suited for the use as a ROM module.
By building the posix library as shared object with an ABI, we
effectively decouple posix-using programs from the library
implementation (which happens to depend on several os-level APIs such as
the VFS).
