"Task attempted to log before it was initialized..."

[Vectrobe]

VS2017 - 15.7.1 CLANG/LLVM 6.0.0 Attempting to build with v100_clang_fafnir results in an immediate failure with this as the only error;

Error	MSB4018	The "MultiToolTask" task failed unexpectedly.
System.InvalidOperationException: Task attempted to log before it was initialized. Message was: Element <DebugInformationFormat> has an invalid value of "ProgramDatabase".
   at Microsoft.Build.Shared.ErrorUtilities.ThrowInvalidOperation(String resourceName, Object[] args)
   at Microsoft.Build.Shared.ErrorUtilities.VerifyThrowInvalidOperation(Boolean condition, String resourceName, Object arg0)
   at Microsoft.Build.Utilities.TaskLoggingHelper.LogError(String subcategory, String errorCode, String helpKeyword, String file, Int32 lineNumber, Int32 columnNumber, Int32 endLineNumber, Int32 endColumnNumber, String message, Object[] messageArgs)
   at Microsoft.Build.Utilities.TaskLoggingHelper.LogErrorFromResources(String messageResourceName, Object[] messageArgs)
   at Microsoft.Build.CPPTasks.VCToolTask.ReadSwitchMap(String propertyName, String[][] switchMap, String value)
   at Microsoft.Build.CPPTasks.ClangCompile.set_DebugInformationFormat(String value)	Macropod	C:\Program Files (x86)\Microsoft Visual Studio\2017\Community\Common7\IDE\VC\VCTargets\Microsoft.Cpp.Clang.targets	130