Switch CMake Generator to Ninja

The default CMake build generator is operating system dependent. In general many projects can benefit from increased build speed and especially rebuild speed of Ninja. To switch the default build generator on any platform, set environment variable CMAKE_GENERATOR.

CMAKE_GENERATOR=Ninja

Ninja executable can be downloaded and extracted. Python users can “pip install ninja”. MacOS Homebrew users can “brew install ninja”.

If using Conan Package Manager, tell Conan to use Ninja by setting environment variable

CONAN_CMAKE_GENERATOR=Ninja