properly handle align 0 on memcpy and memset, warning if asked for
NoExitRuntime
Merge pull request #23 from sunfishcode/incoming

Incoming
1.12.3
Disable the createRewriteLLVMIntrinsicsPass pass.
Use more LLVM-idiomatic error reporting.
Move ExpandI64 into lib/Target/JSBackend.
Update tests for recent changes which result in more parens being used in some places.