Check that the root CMakeLists.txt is correct.
Those checks are necessary for cross-compilation to work well, among other things.
Call cmake with from a build dir for a source dir. cmake_args are added on the command line.
If clean_first is True, we will remove cmake-generated files. Useful when dependencies have changed.
Get the path to cmake modules.
First, assume we are using qibuild from sources, then assume we are using an installed version of qibuild.
Get the list of known cmake generators. Assume cmake is in PATH, or path to cmake is correctly configured in ~/.config/qi/qibuild.xml
Read a CMakeCache.txt file, returning a dict name -> value