Revert "mi: drop now obsolete mioverlay.c"

This reverts commit 65b738ed60.

Requested by Nvidia - their proprietary driver still needs it.

Signed-off-by: Enrico Weigelt, metux IT consult <info@metux.net>
Part-of: <https://gitlab.freedesktop.org/xorg/xserver/-/merge_requests/1843>

mi/meson.build

@@ -9,6 +9,7 @@ srcs_mi = [
     'mifillarc.c',
     'migc.c',
     'miglblt.c',
+    'mioverlay.c',
     'mipointer.c',
     'mipoly.c',
     'mipolypnt.c',

mi/mioverlay.c

@@ -0,0 +1,56 @@
+
+#include <dix-config.h>
+
+#include <X11/X.h>
+
+#include "dix/cursor_priv.h"
+#include "mi/mi_priv.h"
+
+#include "scrnintstr.h"
+#include <X11/extensions/shapeproto.h>
+#include "validate.h"
+#include "windowstr.h"
+#include "gcstruct.h"
+#include "regionstr.h"
+#include "privates.h"
+#include "mivalidate.h"
+#include "mioverlay.h"
+#include "migc.h"
+
+#include "globals.h"
+
+typedef struct {
+    RegionRec exposed;
+    RegionRec borderExposed;
+    RegionPtr borderVisible;
+    DDXPointRec oldAbsCorner;
+} miOverlayValDataRec, *miOverlayValDataPtr;
+
+typedef struct _TreeRec {
+    WindowPtr pWin;
+    struct _TreeRec *parent;
+    struct _TreeRec *firstChild;
+    struct _TreeRec *lastChild;
+    struct _TreeRec *prevSib;
+    struct _TreeRec *nextSib;
+    RegionRec borderClip;
+    RegionRec clipList;
+    unsigned visibility;
+    miOverlayValDataPtr valdata;
+} miOverlayTreeRec, *miOverlayTreePtr;
+
+typedef struct {
+    miOverlayTreePtr tree;
+} miOverlayWindowRec, *miOverlayWindowPtr;
+
+typedef struct {
+    CloseScreenProcPtr CloseScreen;
+    CreateWindowProcPtr CreateWindow;
+    DestroyWindowProcPtr DestroyWindow;
+    UnrealizeWindowProcPtr UnrealizeWindow;
+    RealizeWindowProcPtr RealizeWindow;
+    miOverlayTransFunc MakeTransparent;
+    miOverlayInOverlayFunc InOverlay;
+    Bool underlayMarked;
+    Bool copyUnderlay;
+} miOverlayScreenRec, *miOverlayScreenPtr;