devel/llvm-devel: new snapshot, 32-bit improvements

Apply a patch based on one posted by Mark Millard in the comments of
https://reviews.freebsd.org/D46239 which defaults lld to using a single
thread on 32-bit systems.

Switch lua to 5.4, matching the intalled path of lldb.so.

Sponsored by: 	DARPA, AFRL