gio: add win32 SID helper functions

The code is based from #1351 patch and existing similar code in
gdbusprivate.c. The next commit will replace that existing code with
those helpers.

Signed-off-by: Marc-André Lureau <marcandre.lureau@redhat.com>

gio/gwin32sid.h

@@ -0,0 +1,38 @@
+/* GIO - GLib Input, Output and Streaming Library
+ *
+ * Copyright (C) 2018 Руслан Ижбулатов
+ * Copyright (C) 2022 Red Hat, Inc.
+ *
+ * This library is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public
+ * License as published by the Free Software Foundation; either
+ * version 2.1 of the License, or (at your option) any later version.
+ *
+ * This library is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General
+ * Public License along with this library; if not, see <http://www.gnu.org/licenses/>.
+ *
+ * Author: Руслан Ижбулатов <lrn1986@gmail.com>
+ */
+
+#ifndef __G_WIN32_SID_H__
+#define __G_WIN32_SID_H__
+
+#include <glib.h>
+#include <windows.h>
+
+G_BEGIN_DECLS
+
+SID      * _g_win32_process_get_access_token_sid         (DWORD    process_id,
+                                                          GError **error);
+
+gchar    * _g_win32_sid_to_string                        (SID     *sid,
+                                                          GError **error);
+
+G_END_DECLS
+
+#endif /* __G_WIN32_SID_H__ */