IMHO a broken toolchain is a broken toolchain and that's kind of outside the scope of autoconf -- and I say this despite having banged my head against the wall only too many times as a result of an odd toolchain misconfiguration leading me into chasing autoconf gremlins.
One thing about rust is that it has always treated cross-compiling as a first-class citizen. Cargo is very intentional about the difference between the HOST and TARGET triplets and you can't mix them up unless you are doing so intentionally.
The rsconf feature detection crate was similarly designed with cross-compilation in mind from the start and eschews running binaries in favor of some clever hacks to exfiltrate values during the cross-compilation process.
There is only one rsconf feature (retrieving compile-time constants) that is currently labeled caveat emptor as it does not support cross-compilation; perhaps I can nerdsnipe someone here into figuring out a workaround: https://github.com/mqudsi/rsconf/issues/3
One thing about rust is that it has always treated cross-compiling as a first-class citizen. Cargo is very intentional about the difference between the HOST and TARGET triplets and you can't mix them up unless you are doing so intentionally.
The rsconf feature detection crate was similarly designed with cross-compilation in mind from the start and eschews running binaries in favor of some clever hacks to exfiltrate values during the cross-compilation process.
There is only one rsconf feature (retrieving compile-time constants) that is currently labeled caveat emptor as it does not support cross-compilation; perhaps I can nerdsnipe someone here into figuring out a workaround: https://github.com/mqudsi/rsconf/issues/3