So now introspection users will have to call `GLibUnix.open_pipe()`
rather than `GLibUnix.unix_open_pipe()` — or
`GLibWin32.check_windows_version()` rather than
`GLibWin32.win32_check_windows_version()`.
Signed-off-by: Philip Withnall <pwithnall@gnome.org>
Helps: #3037