[CMake] automatically re-generating makefiles

[Bill Hoffman]

Matthew Woehlke wrote:
> Bill Hoffman wrote:
>> Matthew Woehlke wrote:
>>>> Makefile : cmake_check_build_system
>>>
>>> Shouldn't this rather be:
>>> Makefile: <list of CMakeLists.txt, etc>
>>>     cmake_check_build_system
>>> ?
>>>
>>> ...in which case, the only thing that should get checked is if the 
>>> CMakeLists.txt are newer than the Makefile. So in most cases this 
>>> should be fast.
>>
>> We need to run cmake_check_build_system first because make can not 
>> handle missing depend .h files.
> 
> I'm not saying to stop doing anything that is currently done.
> 
> AFAICT, right now the Makefile itself does not have any dependencies; it 
> seems that adding 'Makefile: <build system files>' with the rule from 
> cmake_check_build_system would fix the original problem. So the question 
> is if running cmake_check_build_system twice in a row can either be 
> eliminated or kept reasonable.
> 
I still don't get the original problem???   We used to have Makefile: 
<build system files>.  It was removed when that work was pushed into 
cmake_check_build_system.

-Bill