gdi32: Implement MirrorRgn.
diff --git a/include/wingdi.h b/include/wingdi.h
index fa68c23..e10bbe9 100644
--- a/include/wingdi.h
+++ b/include/wingdi.h
@@ -3601,6 +3601,7 @@
WINGDIAPI BOOL WINAPI LineTo(HDC,INT,INT);
WINGDIAPI BOOL WINAPI LPtoDP(HDC,LPPOINT,INT);
WINGDIAPI BOOL WINAPI MaskBlt(HDC,INT,INT,INT,INT,HDC,INT,INT,HBITMAP,INT,INT,DWORD);
+WINGDIAPI BOOL WINAPI MirrorRgn(HWND,HRGN);
WINGDIAPI BOOL WINAPI ModifyWorldTransform(HDC,const XFORM *, DWORD);
WINGDIAPI BOOL WINAPI MoveToEx(HDC,INT,INT,LPPOINT);
WINGDIAPI INT WINAPI OffsetClipRgn(HDC,INT,INT);