npth (New GNU Portable Threads Library)

nPth is a library to provide the GNU Pth API and thus a non-preemptive
threads implementation.

In contrast to GNU Pth is is based on the system's standard threads
implementation. This allows the use of libraries which are not compatible
to GNU Pth. Experience with a Windows Pth emulation showed that this
is a solid way to provide a co-routine based framework.

This library is required to compile GnuPG 2.1.