iOS: `CORROSION_HOST_TARGET_LINKER` autodetection doesn't always work

[jschwe]

@jschwe Thank you for your work, with set CORROSION_HOST_TARGET_LINKER everything works fine. I guess you can close this PR.

Originally posted by @chocolacula in #648 (comment)

Ideally, the user wouldn't need to override the CORROSION_HOST_TARGET_LINKER cache variable, and autodetection would "just work".

[jschwe]

@chocolacula May I ask which CMake version you are using? Looking at https://gitlab.kitware.com/cmake/cmake/-/issues/19180, the selected default compiler of CMake seems to have changed in recent CMake versions. Perhaps we should just default to /usr/bin/cc and let the user override that if it doesn't work, instead of asking CMake.

[jschwe]

@chocolacula Thanks for reporting the issue, I hope it should consistently work as expected now.

[chocolacula]

Sorry for the late reply. Just for the history, I faced this issue with quite fresh cmake 4.0 and 4.2