X Server helper

Code from X11's region.h, Region.c, poly.h, and PolyReg.c

Used in Qt GUI (QRegion).

The sources can be found in qt-everywhere-src-5.15.16/qtbase/src/gui/painting/qregion.cpp.

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 Copyright (c) 1987, 1988 X Consortium
 Copyright 1987, 1988 by Digital Equipment Corporation, Maynard, Massachusetts.

X11 License and Historical Permission Notice and Disclaimer.

 Copyright (c) 1987, 1988  X Consortium

 Permission is hereby granted, free of charge, to any person obtaining a copy
 of this software and associated documentation files (the "Software"), to deal
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 all copies or substantial portions of the Software.

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 AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
 CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.

 Except as contained in this notice, the name of the X Consortium shall not be
 used in advertising or otherwise to promote the sale, use or other dealings
 in this Software without prior written authorization from the X Consortium.


 Copyright 1987, 1988 by Digital Equipment Corporation, Maynard, Massachusetts.

                         All Rights Reserved

 Permission to use, copy, modify, and distribute this software and its
 documentation for any purpose and without fee is hereby granted,
 provided that the above copyright notice appear in all copies and that
 both that copyright notice and this permission notice appear in
 supporting documentation, and that the name of Digital not be
 used in advertising or publicity pertaining to distribution of the
 software without specific, written prior permission.

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 ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS,
 WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION,
 ARISING OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS
 SOFTWARE.