[CMake] CMake and it's invocation from MS VC7

[Steve Johns]

> CMake considers upper-case "C" to be a C++ extension by default because 
> is a common convention on UNIX, and Windows is case-insensitive.  Try 
> adding the files like this:
> 
> ADD_LIBRARY(NRC206 addint.c ...)

Thanks for the suggestion.  

I tried this, but the result was still:

   AdditionalOptions = " /TP " 

for each file.  

Is there another approach?