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/vapoursynth/vapoursynth.toml

@@ -0,0 +1,34 @@
+[build]
+type = "autotools"
+
+[build.flags]
+configure = ["--disable-static"]
+post_install = ["install -Dm 644 ../vapoursynth.xml -t $DESTDIR/usr/share/mime/packages/"]
+
+[dependencies]
+build = [
+    "cython",
+    "python-sphinx",
+]
+runtime = [
+    "zimg",
+    "python",
+]
+
+[[manual_sources]]
+file = "vapoursynth.xml"
+
+[package]
+description = "video processing framework with the future in mind"
+homepage = "http://www.vapoursynth.com/"
+license = [
+    "OFL",
+    "LGPL-2.1-or-Later",
+]
+name = "vapoursynth"
+version = "73"
+
+[[source]]
+extract_dir = "$name-$version"
+post_extract = ["./autogen.sh"]
+url = "https://github.com/vapoursynth/vapoursynth.git#R$version"