Attempt to workaround MSVC build issue where I suspect an enum class constant 0 is considered a possible null pointer
Attempt to workaround MSVC build issue where I suspect an enum class constant 0 is considered a possible null pointer

I can't reproduce this so far with web compilers, so throwing this at
the bots to see if it sticks.

git-svn-id: 0ff597fd157e6f4fc38580e8d64ab130330d2411@292155 91177308-0d34-0410-b5e6-96231b3b80d8

llvm-mirror/llvm,llvm-mirror/llvm,apple/swift-llvm,GPUOpen-Drivers/llvm,GPUOpen-Drivers/llvm,llvm-mirror/llvm,llvm-mirror/llvm,apple/swift-llvm,llvm-mirror/llvm,GPUOpen-Drivers/llvm,GPUOpen-Drivers/llvm,llvm-mirror/llvm,llvm-mirror/llvm,apple/swift-llvm,llvm-mirror/llvm,GPUOpen-Drivers/llvm,apple/swift-llvm,apple/swift-llvm,GPUOpen-Drivers/llvm,GPUOpen-Drivers/llvm,llvm-mirror/llvm,GPUOpen-Drivers/llvm,apple/swift-llvm,apple/swift-llvm,apple/swift-llvm