fix a race condition in parallel builds with Visual C

fix a race condition in parallel builds with Visual C

On older VCs a "gmake -j2 ..\generate_uudmap.exe ..\perlglob.exe" will
generate warnings, on newer VCs, a fatal error in 1 or the other cl.exe
process. This is because both cl.exes are trying to lock and write to
vc*0.pdb, the same file. Add PDBOUT option so uudmap and perlglob have
their own pdb files named after themselves and they cant conflict in a
parallel build.