Are you looking for an alternative to emitting C or to using C as the implementation language of the compiler? I'm not totally sure what you're after, and I'm a

Are you looking for an alternative to emitting C or to using C as the implementation language of the compiler? I'm not totally sure what you're after, and I'm a compiler noob, but I've been enjoying Appel's Modern Compiler Implementation in ML, which uses SML as the implementation language and emits RISC machine code or assembly (I think, I haven't actually gotten that far). I don't know how suitable it would be as a stepping stone to forking PHP, but it's something.