Ninja Build System Integration

1st chunk of `doc/hooks/ninja.section.md`

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# ninja {#ninja}

Overrides the build, install, and check phase to run ninja instead of make. You can disable this behavior with the `dontUseNinjaBuild`, `dontUseNinjaInstall`, and `dontUseNinjaCheck`, respectively. Parallel building is enabled by default in Ninja.

Note that if the [Meson setup hook](#meson) is also active, Ninja's install and check phases will be disabled in favor of Meson's.

Title: Ninja Build System Integration

Summary

This section describes how Nixpkgs integrates with the Ninja build system. It explains how the build, install, and check phases can be overridden to use Ninja instead of Make, and how to disable this behavior. It also notes the interaction with the Meson setup hook, where Meson's install and check phases take precedence over Ninja's.