Run cmparseMSBuildXML.py on masm.xml to generate our flag tables:
python cmparseMSBuildXML.py -x ".../MSBuild/Microsoft.Cpp/v4.0/BuildCustomizations/masm.xml" > cmVS10MASMFlagTable.h
python cmparseMSBuildXML.py -x ".../MSBuild/Microsoft.Cpp/v4.0/V110/BuildCustomizations/masm.xml" > cmVS11MASMFlagTable.h
python cmparseMSBuildXML.py -x ".../MSBuild/Microsoft.Cpp/v4.0/V120/BuildCustomizations/masm.xml" > cmVS12MASMFlagTable.h
python cmparseMSBuildXML.py -x ".../MSBuild/Microsoft.Cpp/v4.0/V140/BuildCustomizations/masm.xml" > cmVS14MASMFlagTable.h
Fix up the declaration names at the top of each file.