Add a probably incorrect find line to remove "empty" directories

They aren't really empty, they contain only a CVS directory, but fairly
sure we don't want them.
Use the system atof() on vax instead of perl's

Because numbers on vax are special.

Thanks to miod@ for noting that they are special and leont on
irc.perl.org#p5p for the fix.

This resolves some Floating point exceptions in perl, although there
are still some things that vax gets wrong.

Probably should figure out how to make this the default for vax though.
Centralize the cvsroot extractor in utils.pm
Use the patched perl to merge patches
Properly escape the find example
Add support to cvs_rm_add for ignoring some unicore files

Because we don't actually want to commit *all* the changes
Support SKIP_UNICORE_PATCH in make_src_patch

Although it's silly to do, doesn't buy much but pain.
Remove something that happens in cvs_rm_add, so we don't need to repeat
use the cvs_rm_add from utils

Because that one supports skipping unicore.
More generated unicore files that shouldn't be deleted
Don't put the cvs import command into a variable

I couldn't figure out how to escape everything to make it happy.
Remove a crufty cd $OLDPWD

Which was breaking things
Do the unicore files in a separate commit

They are large and generated so just put them in a commit that can be
ignored more easily.