We have a lot of code duplication in all our calls to SetupNativeCompilation. This patch introduces a pair of functions, SetupJdkLibrary and SetupJdkExecutable, which wraps SetupNativeCompilation and sets up typical default values for our JDK libraries.

The long-term idea here is that even more functionality (e.g. basic LDFLAGS and CFLAGS) should move into these two functions, but for simplicity, this patch just does the most basic cleanup.

Not all compilations were easily converted. Those were left behind at using SetupNativeCompilation, just as before. If possible, they should be fixed and converted at a later date.