This library provides weak aliases for pthread functions not provided
 in libc or otherwise available by default. Libraries like libxcb rely
 on pthread stubs to use pthreads optionally, becoming thread-safe when
 linked to libpthread, while avoiding any performance hit when running
 single-threaded. libpthread-stubs supports this behavior even on
 platforms which do not supply all the necessary pthread stubs.
 .
 On platforms which already supply all the necessary pthread stubs, this
 package ships only the pkg-config file pthread-stubs.pc, to allow
 libraries to unconditionally express a dependency on pthread-stubs and
 still obtain correct behavior.