Move adding of definitions into cmGlobalVisualStudioGenerator to share code and avoid duplicate architecture string literals.
Since the parent commit the local generator Version ivar may be compared for ordering. Convert comparisons: "==VS10" becomes ">=VS10" "!=VS10" becomes "< VS10" to support an explicit enumeration value for VS11 with no change in behavior.
With "Visual Studio 2011" the launcher does not recognize the version of the *.sln files. With "Visual Studio 11" it does.