threads

Add threads support for various packages. Usually pthreads

Name	Category	Description
x264	media-libs	A free library for encoding X264/AVC streams
x264-encoder	media-video	A free commandline encoder for X264/AVC streams
xaos	x11-misc	Very fast real-time fractal zoomer
xerces-c	dev-libs	A validating XML parser written in a portable subset of C++
xmlrpc-c	dev-libs	A lightweight RPC library based on XML and HTTP
xsb	dev-lang	XSB is a logic programming and deductive database system
xvid	media-libs	High performance/quality MPEG-4 video de-/encoding solution
yap	dev-lang	YAP is a high-performance Prolog compiler
yass	sci-biology	Genomic similarity search with multiple transition constrained spaced seeds
zbar	media-gfx	Library and tools for reading barcodes from images or video
zstd	app-arch	zstd fast compression library