[CMake] cmake_check_build_system

[Christian Lang]

Hello,
>> when executing a Makefile generated by cmake, one of the first actions
>> it does is to check the cmake build system (target
>> cmake_check_build_system). For some reason we want to avoid this. Is
>> this possible without changing the Makefile manually?
>>     
>
> The makefiles will not work correctly without that step.
> Generated header files will not work, dependencies will not stay
> up-to-date, and several other things.
>   

Yes, I know that it is an important step in general. In our case, 
nothing will change as long as the generated Makefile exists. However, 
it is not called "Makefile", but "CMakefile". We start the build-process 
by "make -f CMakefile", but because of cmake_check_build_system cmake 
builds a new "Makefile", overwriting the existing handwritten one - and 
this is what we want to avoid.

Christian