How to use llvm to cross-compile to C?

[Philipp_Klaus_Krause]

I want to use llvm to develop for an embedded system. Ther is a free C
compiler targeting the embedded system. I hope llvm will provide a way
to use other languages, e.g. using clang to compile C++.

How can I do this? How do I tell llvm the size of ints on the
target, etc?

Philipp