BaseTools/Conf: Support LLVM39 and LLVM40 in CLANG38 toolchain
BaseTools/Conf: Support LLVM39 and LLVM40 in CLANG38 toolchain

https://bugzilla.tianocore.org/show_bug.cgi?id=676
Add LLVM39 and LLVM40 support in CLANG38 toolchain

Contributed-under: TianoCore Contribution Agreement 1.1
Signed-off-by: Steven Shi <4f7a0884debfd9139745b184e69c58dae2b3e6ce@intel.com>
Reviewed-by: Liming Gao <6480311aeeb4b006862f6d13ebabddc03f51e507@intel.com>

MattDevo/edk2,MattDevo/edk2,MattDevo/edk2,MattDevo/edk2,MattDevo/edk2,MattDevo/edk2,MattDevo/edk2,MattDevo/edk2