Currently, there is no way to run the install step for a CMake project in parallel. This can result in long install times for some projects. The Ninja generator creates `sub/dir/install/local` targets which install a particular directory without installing its subdirectories. For a project that does not rely on a global state modified by the install code, these targets can be executed simultaneously to fully parallelize the installation. There are two things needed to make this possible: 1. Create an additional target (`install/local/all`?) which depends all other `../install/local` targets. 2. Add an option (`CMAKE_INSTALL_LOCAL_PARALLEL`?) to remove the console pool from the `../install/local` targets so that they can run in parallel.