Don't install static library files of statically linked extensions

Don't install static library files of statically linked extensions
when using a shared perl library. The files are not needed, and this
fixes a problem building PAR-Packer on Win32 with a debug build of
perl. (If Win32CORE.lib gets installed then PAR-Packer wants to link
against it and its PDB file, vc60.pdb, but the latter is not installed.)
Also skip installing a few other unnecessary files.

Subject: Re: Problem in Win32CORE when building PAR-Packer-0.975 with bleadperl on Win32
Message-ID: <468E2566.8090504@uk.radan.com>

p4raw-id: //depot/perl@31570