swift234

SIL: Introduce a SILGlobalVariable concept.

This will let us control linkage and emit new variables independent of the AST in SILGen. In particular, for lazy global initialization, we need to emit a unique internal once predicate for every top-level pattern binding. Switching everything over is a bit much to reengineer all at once, so for now, it can coexist with the globals map that is already there.

Swift SVN r10509