added absolutely broken cpp code after painfull debugging session

vendored/SDL/include/SDL3/SDL_test_compare.h

@@ -0,0 +1,76 @@
+/*
+  Simple DirectMedia Layer
+  Copyright (C) 1997-2025 Sam Lantinga <slouken@libsdl.org>
+
+  This software is provided 'as-is', without any express or implied
+  warranty.  In no event will the authors be held liable for any damages
+  arising from the use of this software.
+
+  Permission is granted to anyone to use this software for any purpose,
+  including commercial applications, and to alter it and redistribute it
+  freely, subject to the following restrictions:
+
+  1. The origin of this software must not be misrepresented; you must not
+     claim that you wrote the original software. If you use this software
+     in a product, an acknowledgment in the product documentation would be
+     appreciated but is not required.
+  2. Altered source versions must be plainly marked as such, and must not be
+     misrepresented as being the original software.
+  3. This notice may not be removed or altered from any source distribution.
+*/
+
+/**
+ *  Comparison function of SDL test framework.
+ *
+ *  This code is a part of the SDL test library, not the main SDL library.
+ */
+
+/*
+
+ Defines comparison functions (i.e. for surfaces).
+
+*/
+
+#ifndef SDL_test_compare_h_
+#define SDL_test_compare_h_
+
+#include <SDL3/SDL.h>
+
+#include <SDL3/SDL_begin_code.h>
+/* Set up for C function definitions, even when using C++ */
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+/**
+ * Compares a surface and with reference image data for equality
+ *
+ * \param surface Surface used in comparison
+ * \param referenceSurface Test Surface used in comparison
+ * \param allowable_error Allowable difference (=sum of squared difference for each RGB component) in blending accuracy.
+ *
+ * \returns 0 if comparison succeeded, >0 (=number of pixels for which the comparison failed) if comparison failed, -1 if any of the surfaces were NULL, -2 if the surface sizes differ.
+ */
+int SDLCALL SDLTest_CompareSurfaces(SDL_Surface *surface, SDL_Surface *referenceSurface, int allowable_error);
+
+/**
+ * Compares 2 memory blocks for equality
+ *
+ * \param actual Memory used in comparison, displayed on the left
+ * \param size_actual Size of actual in bytes
+ * \param reference Reference memory, displayed on the right
+ * \param size_reference Size of reference in bytes
+ *
+ * \returns 0 if the left and right memory block are equal, non-zero if they are non-equal.
+ *
+ * \since This function is available since SDL 3.2.0.
+ */
+int SDLCALL SDLTest_CompareMemory(const void *actual, size_t size_actual, const void *reference, size_t size_reference);
+
+/* Ends C function definitions when using C++ */
+#ifdef __cplusplus
+}
+#endif
+#include <SDL3/SDL_close_code.h>
+
+#endif /* SDL_test_compare_h_ */