This finally blew up spectacularly on Windows because we now have
packages delivering external libraries to the solver, where the
libraries are not defined by Library class, which leads to accidental
inheritance of AUXTARGETS variable and failure to deliver nonexistent
UnpackedTarball/.../libpq/postgresql-sdbc-impl.uno.dll

Remove the custom deliver rule that uses AUXTARGETS, and instead
let those files be handled individually by default Package.mk rules.

This requires a dummy touch rule for each file, and unfortunately a
pattern rule cannot be used here because of silly naming differences
between implibs and dlls on Windows...

AUXTARGETS do not cause problems for clean targets because there is no
interdependency there, so keep them there.

Change-Id: I2138f635334ff4517a2d31ef91cfd03a46745fd6