infixSalt
suffixSalt
I hate the thing too even though I made it, and rather just get rid of it. But we can't do that yet. In the meantime, this brings us more inline with autoconf and will make it slightly easier for me to write a pkg-config wrapper, which we need.
llvm uses response files in bootstrapping. It’s okay for them to happen even though we don’t use expandResponseParams here right now.