[CMake] Visual Studio and Windows Mobile SDKs

[Andreas Pokorny]

Hello,
Right now the WindowsCE Version is harcoded to 5.0 in the macros and
the subsystem definition.
A better solution might be to use the CMAKE_SYSTEM_VERSION. For that I
would need a decimal-string
to integer or hex conversion and reasonable defaults when
CMAKE_SYSTEM_VERSION is not set.
Is there already a cmake function to do that?

kind regards
Andreas Pokorny