[CMake] Make CMAKE_EXPORT_COMPILE_COMMANDS not default?

[Stephen Kelly]

Alexander Neundorf wrote:

> It sounds to me a bit more like it should be an additional "extra"
> generator, i.e. generate makefiles/ninja files and additionally this json
> file.

Hmm, the first thing I thought when I saw your kate project feature was that 
it should be implemented more like CMAKE_EXPORT_COMPILE_COMMANDS. 

Otherwise there's a combinatorial explosion of extra generators. There would 
have to be a 'MinGW Makefiles - Kate Project - ExportCommands' generator 
etc.

I don't think 'extra generator' axis is a good extension vector for 
generation features.

Thanks,

Steve.