Include unistd.h only on *NIX and define items as necessary on Windows,
also replace instances of ssize_t with the GLib-equivilant gssize so to fix
the build on platforms that do not have ssize_t, such as Visual C++.
https://bugzilla.gnome.org/show_bug.cgi?id=711047
Very many testcases, some GLib tools (resource compiler, etc) and
GApplication were calling g_type_init().
Remove those uses, as they are no longer required.
https://bugzilla.gnome.org/show_bug.cgi?id=686161
Implement test case suggested by Ryan Lortie on bug:
https://bugzilla.gnome.org/show_bug.cgi?id=679288
"There is a potential race here that's really unlikely to happen, but
here we go: We are trying to read from the same socket in two threads.
Some data comes. That causes the poll() in both threads (above) to
finish running. Then the cancellable is checked above. We now find
ourselves here. Only one thread will read the data. The other will
block on this function. Then the user may cancel the cancellable while
we are blocked here, but we will stay blocked...."
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.
