Maybe an IR language would be some kind of less worse compromise for portability and to avoid complex syntax (C is already too rich and flexible). For instance

Maybe an IR language would be some kind of less worse compromise for portability and to avoid complex syntax (C is already too rich and flexible). For instance like QBE (http://c9x.me/compile http://c9x.me/compile). There is llvm, but its grotesque and absurd c++ complexity does exclude it, de-facto. The main pitfall with IR (like QBE), is intrinsics, because QBE does a bit of optimization and writting "hardware accelerated" intrinsics in a portable way forces the IR to generalize some instruction properties which "could" make even its simple optimization passes a nightmare. That said, I would go RISC-V assembly (64bits) with a conservative usage of a pre-processor.