Add new packages and build scripts for various libraries

- Added Nuklear GUI library with build script and configuration.
- Introduced OpenH264 encoder/decoder with build configuration.
- Added PortAudio library for audio I/O with custom build script.
- Included Python Execnet for multi-Python deployment.
- Added Pytest Xdist plugin for distributed testing.
- Introduced Shaderc for shader compilation tools.
- Added Snappy compression library with necessary patches and configuration.
- Included SoundTouch audio processing library with build configuration.
- Added SRT library for secure reliable transport.
- Introduced VapourSynth video processing framework with configuration.
- Added Vid.stab for video stabilization.
- Included WebRTC Audio Processing library with build configuration.
- Added X264 video encoding library with patches for POSIX compliance.
- Introduced X265 video encoder with build configuration.
- Added XKeyboard Config for X keyboard configuration files.
- Included Xorg XKBComp for keyboard description compilation.
- Added Xvidcore MPEG-4 video codec library with configuration.
- Introduced ZeroMQ messaging system with patches and build configuration.
- Added Zimg library for scaling and colorspace conversion.

extra/xkeyboard-config/xkeyboard-config.toml

@@ -0,0 +1,34 @@
+[build]
+type = "meson"
+
+[build.flags]
+build_dir = "build"
+configure = [
+    "-Dcompat-rules=true",
+    "-Dxorg-rules-symlinks=true",
+]
+
+[dependencies]
+build = [
+    "xorg-xkbcomp",
+    "libxslt",
+    "python",
+    "meson",
+]
+test = [
+    "python-pytest",
+    "python-pytest-xdist",
+    "libxkbcommon"
+]
+
+[package]
+description = "X keyboard configuration files"
+homepage = "https://gitlab.freedesktop.org/xkeyboard-config/xkeyboard-config"
+license = "LicenseRef-xkeyboard-config"
+name = "xkeyboard-config"
+version = "2.47"
+
+[[source]]
+extract_dir = "$name-$version"
+sha256 = "e59984416a72d58b46a52bfec1b1361aa7d84354628227ee2783626c7a6db6b6"
+url = "https://xorg.freedesktop.org/archive/individual/data/$name/$name-$version.tar.xz"