Win32 driver: Fix memory leak / invalid pointer to free() when re-calculating buffer position in a specific situation.

Thanks to @nathanwiebe for reporting this.

changelog.txt

@@ -19,6 +19,7 @@ FEATURE:    STM32LTDC driver: Support double buffering. This introduces STM32LTD
 FIX:        STM32LTDC driver: Fix bug in gdisp_lld_blit_area() which affected blits with source coordinates other than (0, 0).
 FIX:        Improve /demos/benchmarks/rectangles.
 FIX:        Win32 driver: Fix buffer position calculation in gdisp_lld_blit_area().
+FIX:        Win32 driver: Fix memory leak / invalid pointer to free() when re-calculating buffer position in a specific situation.
 
 
 *** Release 2.9 ***

drivers/multiple/Win32/gdisp_lld_Win32.c

@@ -1279,11 +1279,17 @@ LLDSPEC gBool gdisp_lld_init(GDisplay *g) {
 		gPixel	*		buffer;
 		RECT			rect;
 		BITMAPV4HEADER	bmpInfo;
+		#if GDISP_NEED_CONTROL
+			gPixel* bufferBase;
+		#endif
 
 		// Make everything relative to the start of the line
 		priv = g->priv;
 		buffer = g->p.ptr;
 		buffer += g->p.x2 * g->p.y1 + g->p.x1;
+		#if GDISP_NEED_CONTROL
+			bufferBase = buffer;	// Keep pointer to original buffer for correct free()-ing later on
+		#endif
 
 		memset(&bmpInfo, 0, sizeof(bmpInfo));
 		bmpInfo.bV4Size = sizeof(bmpInfo);
@@ -1369,7 +1375,7 @@ LLDSPEC gBool gdisp_lld_init(GDisplay *g) {
 		#endif
 
 		#if GDISP_NEED_CONTROL
-			if (buffer != (gPixel *)g->p.ptr)
+			if (bufferBase != buffer)
 				free(buffer);
 		#endif
 	}