[llvm] r228000 - [LTO API] split lto_codegen_compile to lto_codegen_optimize and

[Rafael Espíndola]

> +extern unsigned int
> +lto_api_version() {
> +  return LTO_API_VERSION;
> +}

This was causing link errors on linux. I have moved the implementation
out of line in r228012.

Cheers,
Rafael