Add support for zlib-ng

[catatsuy]

This pull request adds support for building Nginx with the zlib-ng compression library, alongside the existing zlib support. It introduces new configuration options, updates the builder logic to handle zlib-ng, and adds a dedicated workflow to test building with zlib-ng. The changes ensure zlib-ng can be selected, downloaded, built, and tested similarly to other supported libraries.

Key changes include:

zlib-ng Support in Build System:

• Added ComponentZlibNG to the builder, with corresponding constants for version and download URL, and updated methods to handle naming, download URLs, and source paths for zlib-ng (builder/const.go, builder/builder.go). [1] [2] [3] [4] [5] [6] [7]
• Updated MakeBuilder and related logic to recognize zlib-ng as a separate component and handle its download prefix.

CLI and Build Option Enhancements:

• Added new CLI flags and options for enabling zlib-ng (--zlib-ng) and specifying its version (--zlibngversion). Updated option descriptions and defaults accordingly (option.go). [1] [2]
• Updated the main build logic to recognize and process the zlib-ng options, including parallel downloading and extraction, and inclusion as a dependency when selected (nginx-build.go). [1] [2] [3] [4] [5]

Testing and Workflow:

• Added a new GitHub Actions workflow job to build and test Nginx with zlib-ng, including patch application and configuration (.github/workflows/go.yml, config/configure.zlibng.example). [1] [2]
• Extended builder tests to cover zlib-ng, ensuring correct naming and builder setup (builder/builder_test.go). [1] [2]

[catatsuy]

refs: nginx/nginx#644