Build traceback with new CLANG35 toolset

[Bruce Cran <bruce@cran.org.uk>]

I was just testing the new GCC5 and CLANG35 toolsets that have landed in 
git master: GCC5 works perfectly, but with CLANG35 I get the following 
log and traceback:

Build environment: Linux-4.6.4-2-default-x86_64-with-SuSE-20160728-x86_64
Build start time: 12:12:40, Aug.02 2016

WORKSPACE        = /mnt/user/workspace/edk2
ECP_SOURCE       = /mnt/user/workspace/edk2/EdkCompatibilityPkg
EDK_SOURCE       = /mnt/user/workspace/edk2/EdkCompatibilityPkg
EFI_SOURCE       = /mnt/user/workspace/edk2/EdkCompatibilityPkg
EDK_TOOLS_PATH   = /mnt/user/workspace/edk2/BaseTools

Architecture(s)  = X64
Build target     = RELEASE
Toolchain        = CLANG35

Active Platform          = /mnt/user/workspace/edk2/MyPkg/MyPkg.dsc

Processing meta-data .

build.py...
  : error C0DE: Unknown fatal error when processing 
[/mnt/user/workspace/edk2/MyPkg/MyPkg.inf]

(Please send email to edk2-devel@lists.01.org for help, attaching 
following call stack trace!)

(Python 2.7.12 on linux2) Traceback (most recent call last):
   File 
"/mnt/user/workspace/edk2/BaseTools/BinWrappers/PosixLike/../../Source/Python/build/build.py", 
line 2270, in Main
     MyBuild.Launch()
   File 
"/mnt/user/workspace/edk2/BaseTools/BinWrappers/PosixLike/../../Source/Python/build/build.py", 
line 2022, in Launch
     self._MultiThreadBuildPlatform()
   File 
"/mnt/user/workspace/edk2/BaseTools/BinWrappers/PosixLike/../../Source/Python/build/build.py", 
line 1857, in _MultiThreadBuildPlatform
     Ma.CreateMakeFile(True)
   File 
"/mnt/user/workspace/edk2/BaseTools/Source/Python/AutoGen/AutoGen.py", 
line 3923, in CreateMakeFile
     if Makefile.Generate():
   File 
"/mnt/user/workspace/edk2/BaseTools/Source/Python/AutoGen/GenMake.py", 
line 184, in Generate
     FileContent = self._TEMPLATE_.Replace(self._TemplateDict)
   File 
"/mnt/user/workspace/edk2/BaseTools/Source/Python/AutoGen/GenMake.py", 
line 525, in _CreateTemplateDict
     RespDict = self.CommandExceedLimit()
   File 
"/mnt/user/workspace/edk2/BaseTools/Source/Python/AutoGen/GenMake.py", 
line 716, in CommandExceedLimit
     Str = self._AutoGenObject._BuildOption[Tool]['FLAGS']
KeyError: 'FLAGS'

-- 
Bruce