@theruran @janneke the Hurd surely can run GCC and cross-compile Linux; but I'm not sure you would be winning much, for two reasons:
1. It's nowhere near as trivial to do "syscalls" as on Linux — on Linux you place some values into some registers and perform "int 0x80" or "syscall", and that's it, you've called write or exit. On the Hurd, these all are implemented in glibc on top of Mach IPC, and that needs quite a lot of code to happen.