Add warning if someone passes `.c` and `.h` source explicitly when not running Scala native

[lwronski]

Is your feature request related to a problem? Please describe. https://github.com/VirtusLab/scala-cli/pull/812 add support to embedded resources in SN binary and allow using c files as regular inputs. To avoid misunderstandings it should be added warning when someone passes .c and .h source explicitly when not running Scala native.

Additional context Issue created base on comment in https://github.com/VirtusLab/scala-cli/pull/812#discussion_r955983934.