To resolve
undefined reference to `_swift_exceptionPersonality'
you need to tell Clang to disable exceptions support for the C++ code (which is likely what you want anyway, most embedded platforms don't want the relatively heavyweight unwinding runtime that is needed for C++ exceptions to work...):
-Xcc -fno-exceptions
-Xcc -fno-rtti
These are also in the sample setup in https://github.com/apple/swift-matter-examples/blob/main/empty-template/main/CMakeLists.txt#L32.