Build gtk4 with gstreamer for playing videos

[alexkrz]

Output of brew config

HOMEBREW_VERSION: 5.0.4-21-gca53c10
ORIGIN: https://github.com/Homebrew/brew
HEAD: ca53c10842e9332ed406cd0d062abbf9a2e732e8
Last commit: 36 minutes ago
Branch: main
Core tap JSON: 03 Dec 10:18 UTC
Core cask tap JSON: 03 Dec 10:18 UTC
HOMEBREW_PREFIX: /opt/homebrew
HOMEBREW_CASK_OPTS: []
HOMEBREW_DISPLAY: /private/tmp/com.apple.launchd.T6MOOHfrJ8/org.xquartz:0
HOMEBREW_DOWNLOAD_CONCURRENCY: 16
HOMEBREW_FORBID_PACKAGES_FROM_PATHS: set
HOMEBREW_MAKE_JOBS: 8
HOMEBREW_SORBET_RUNTIME: set
Homebrew Ruby: 3.4.7 => /opt/homebrew/Library/Homebrew/vendor/portable-ruby/3.4.7/bin/ruby
CPU: octa-core 64-bit arm_blizzard_avalanche
Clang: 17.0.0 build 1700
Git: 2.50.1 => /Applications/Xcode.app/Contents/Developer/usr/bin/git
Curl: 8.7.1 => /usr/bin/curl
macOS: 26.1-arm64
CLT: 26.1.0.0.1.1761104275
Xcode: 26.1.1
Metal Toolchain: N/A
Rosetta 2: false

Output of brew doctor

Your system is ready to brew.

Description of issue

The current media backend for gtk4 from homebrew is None.
This means I cannot play videos when running the video player from gtk4-demo.

The necessary change would be to set "-Dmedia-gstreamer=enabled" in https://github.com/Homebrew/homebrew-core/blob/3683d05278207a4c98ce4c189c7a4239471ed69d/Formula/g/gtk4.rb#L74

I have tried it myself, but it currently leads to circular dependencies, as gtk4 would then depend on gstreamer and gstreamer depends on gtk4.

Any ideas how to fix this?