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/jack2/build.sh

@@ -0,0 +1,30 @@
+#!/bin/sh
+set -eu
+
+depot_build() {
+    rm -rf ./waflib
+
+    export CXXFLAGS="${CXXFLAGS:+$CXXFLAGS }-I/usr/include/db5.3"
+    export LDFLAGS="${LDFLAGS:+$LDFLAGS }-ldb-5.3"
+    export LINKFLAGS="$LDFLAGS"
+    export PYTHONPATH="${PWD}${PYTHONPATH:+:$PYTHONPATH}"
+
+    waf configure \
+        --prefix=/usr \
+        --htmldir=/usr/share/doc/jack2/html \
+        --autostart=none \
+        --doxygen=yes \
+        --classic \
+        --dbus
+
+    waf build
+}
+
+depot_install() {
+    export PYTHONPATH="${PWD}${PYTHONPATH:+:$PYTHONPATH}"
+    waf install --destdir="$DESTDIR"
+
+    install -Dm755 ../jackd.initd "$DESTDIR/etc/init.d/jackd"
+    install -Dm644 ../jackd.confd "$DESTDIR/etc/conf.d/jackd"
+    install -d "$DESTDIR/etc/jack"
+}