Support/PathV2: Fix make_absolute() to match is_absolute() and not expect to find root names on Unix.  - This fixes make_absolute to not basically always call current_path() on    Unix systems.  - I think the API probably needs cleanup in this area, but I'll let Michael    handle that.
Support/PathV2: Fix make_absolute() to match is_absolute() and not expect to
find root names on Unix.
 - This fixes make_absolute to not basically always call current_path() on
   Unix systems.
 - I think the API probably needs cleanup in this area, but I'll let Michael
   handle that.

git-svn-id: 0ff597fd157e6f4fc38580e8d64ab130330d2411@151681 91177308-0d34-0410-b5e6-96231b3b80d8

llvm-mirror/llvm,llvm-mirror/llvm,chubbymaggie/asap,GPUOpen-Drivers/llvm,llvm-mirror/llvm,chubbymaggie/asap,dslab-epfl/asap,GPUOpen-Drivers/llvm,GPUOpen-Drivers/llvm,GPUOpen-Drivers/llvm,dslab-epfl/asap,apple/swift-llvm,llvm-mirror/llvm,apple/swift-llvm,llvm-mirror/llvm,chubbymaggie/asap,llvm-mirror/llvm,dslab-epfl/asap,apple/swift-llvm,GPUOpen-Drivers/llvm,apple/swift-llvm,GPUOpen-Drivers/llvm,chubbymaggie/asap,apple/swift-llvm,GPUOpen-Drivers/llvm,llvm-mirror/llvm,llvm-mirror/llvm,dslab-epfl/asap,GPUOpen-Drivers/llvm,apple/swift-llvm,apple/swift-llvm,chubbymaggie/asap,apple/swift-llvm,llvm-mirror/llvm,dslab-epfl/asap,dslab-epfl/asap,chubbymaggie/asap,dslab-epfl/asap