Bug in g++ --syntax-only

[Tom Tromey]

I was suprised by this:

    creche. g++ --syntax-only foo.cc 
    g++: -lstdc++: linker input file unused because linking not done
    g++: -lm: linker input file unused because linking not done

I think addition of those -l flags should be disabled when
--syntax-only is given.  I find these messages counterintuitive.

Tom