This is the DiOS host library (libdios-host.a). It is a thin shim on top of
the platform libc to fill in some of the functionality that is available in
DiOS but might be missing or broken on some host platforms. The code here is
based on gnulib, which is covered by GPLv3.

The headers are private and are never used outside of building libdios-host.a
itself. The compiled code is automatically linked into binaries when they are
linked using `divcc`. For now, the host library covers the stdio_ext.h
subfamily of functions available on MUSL (and stubbed in DiOS) but not
available in glibc. Additionally, it contains an `fflush` wrapper that
corrects various platform problems related to input streams.
