1. build the static modules first, before libpam so that the static
libpam can link against the module .a files.
2. build the modules after the dynamic libpam is build, so that the
dynamic modules can link against the dynamic libpam.
upon, because:
* it's MUCH quicker; no need to calculate the OBJDIRS of every library
we might require in every subdir.
(make obj drops from 21s to 3s on my system.)
* it's more robust when building to a fresh DESTDIR.
