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/mpg123/mpg123.toml

@@ -0,0 +1,29 @@
+[build]
+type = "autotools"
+
+[build.flags]
+configure = [
+    "--enable-int-quality",
+    "--with-audio=alsa oss sdl jack",
+]
+
+[dependencies]
+build = ["sdl2", "jack"]
+optional = [
+    "sdl2",
+    "perl",
+    "jack"
+]
+runtime = ["alsa-lib"]
+
+[package]
+description = "Console based real time MPEG Audio Player for Layer 1, 2 and 3"
+homepage = "https://mpg123.de/"
+license = "LGPL-2.1-only"
+name = "mpg123"
+version = "1.33.4"
+
+[[source]]
+extract_dir = "$name-$version"
+sha256 = "md5:1dcce56af481df25cb3a26db6fcaec75"
+url = "https://downloads.sourceforge.net/sourceforge/mpg123/mpg123-$version.tar.bz2"