Don't check in the LibDeps.txt and FinalLibDeps.txt files to CVS because
the content differs from platform to platform. Instead, adjust the makefile
so that a dummy llvm-config is built if Perl is not available.
llvm-svn: 28084
1. If Perl is not available, don't run Perl dependent targets.
2. Check in FinalLibDeps.txt for build environments that can't build it
because there's no Perl processor.
3. Ensure that FinalLibDeps.txt depends on LibDeps.txt so it is
automatically regenerated.
4. Support objdir != srcdir building.
llvm-svn: 27915