It sucks to have the lists of public headers duplicated in the
Makefile.am files and the glib.vsprops file. But it isn't exactly easy
to work around all the weirdness in autotools, Visual Studio, and bat
files either to do it another way.
Correspond to GUnixInputStream and GUnixOutputStream. No true async
support though. But that is how the Win32 API is, for files not
explicitly opened for so-called overlapped IO.
The API to create these streams takes Win32 HANDLEs. Not file
descriptors, because file descriptors are specific to the C library
used. The user code and GLib might be using different C libraries.
Also add a test program for the new classes, and a gio-windows-2.0.pc
file.
