This might make a difference in compile times. If for example we copy a files like newton.hpp unconditionally then every compilation unit which (transitively) depends on newton.hpp will need to be recompiled.
If we only copy when newton.hpp has changed, we can likely avoid recompiling pointlessly.
This might make a difference in compile times. If for example we copy a files like
newton.hppunconditionally then every compilation unit which (transitively) depends onnewton.hppwill need to be recompiled.If we only copy when
newton.hpphas changed, we can likely avoid recompiling pointlessly.