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/shaderc/shaderc.toml

@@ -0,0 +1,41 @@
+[build]
+type = "cmake"
+
+[build.flags]
+build_dir = "build"
+configure = [
+    "-G Ninja",
+    "-DSHADERC_SKIP_TESTS=ON",
+    "-DPYTHON_EXECUTABLE=python",
+    "-Dglslang_SOURCE_DIR=/usr/include/glslang",
+]
+post_install = [ "rm $DESTDIR/usr/lib/pkgconfig/shaderc_static.pc" ]
+
+[dependencies]
+build = [
+    "cmake",
+    "ninja",
+    "python",
+    "spirv-headers",
+]
+runtime = [
+    "glibc",
+    "glslang",
+    "libunwind",
+    "libcxx",
+    "spirv-tools",
+]
+
+[package]
+description = "Collection of tools, libraries and tests for shader compilation"
+homepage = "https://github.com/google/shaderc"
+license = "Apache-2.0"
+name = "shaderc"
+version = "2026.1"
+
+[[source]]
+extract_dir = "$name-$version"
+sha256 = "245002feccbe7f8361b223545a5654cea69780745886872d7efff50a38d96c66"
+url = "https://github.com/google/shaderc/archive/v$version/$name-$version.tar.gz"
+post_extract = [ "sed '/examples/d;/third_party/d' -i CMakeLists.txt && sed '/build-version/d' -i glslc/CMakeLists.txt && printf '\"%s\\\\n\"\\n\"%s\\\\n\"\\n\"%s\\\\n\"\\n' \"$version\" \"$(depot info spirv-tools | sed -n 's/.* v\\([^ ]*\\)$/\\1/p' | sed '1q;s/-.*//')\" \"$(depot info glslang | sed -n 's/.* v\\([^ ]*\\)$/\\1/p' | sed '1q;s/-.*//')\" > glslc/src/build-version.inc" ]
+# ^ PITA to write, used ai