Removed the limit on the size of the SDL error message

Also added SDL_GetOriginalMemoryFunctions()

Fixes https://github.com/libsdl-org/SDL/issues/5795

src/dynapi/SDL2.exports

@@ -851,3 +851,4 @@
 ++'_SDL_utf8strnlen'.'SDL2.dll'.'SDL_utf8strnlen'
 # ++'_SDL_GDKGetTaskQueue'.'SDL2.dll'.'SDL_GDKGetTaskQueue'
 # ++'_SDL_GDKRunApp'.'SDL2.dll'.'SDL_GDKRunApp'
+++'_SDL_GetOriginalMemoryFunctions'.'SDL2.dll'.'SDL_GetOriginalMemoryFunctions'

src/dynapi/SDL_dynapi.c

@@ -71,11 +71,25 @@ static void SDL_InitDynamicAPI(void);
 
 #define SDL_DYNAPI_VARARGS(_static, name, initcall) \
     _static int SDLCALL SDL_SetError##name(SDL_PRINTF_FORMAT_STRING const char *fmt, ...) { \
-        char buf[512]; /* !!! FIXME: dynamic allocation */ \
+        char buf[128], *str = buf; \
+        int result; \
         va_list ap; initcall; va_start(ap, fmt); \
-        jump_table.SDL_vsnprintf(buf, sizeof (buf), fmt, ap); \
+        result = jump_table.SDL_vsnprintf(buf, sizeof(buf), fmt, ap); \
+        if (result >= 0 && (size_t)result >= sizeof(buf)) { \
+            size_t len = (size_t)result + 1; \
+            str = (char *)jump_table.SDL_malloc(len); \
+            if (str) { \
+                result = jump_table.SDL_vsnprintf(str, len, fmt, ap); \
+            } \
+        } \
         va_end(ap); \
-        return jump_table.SDL_SetError("%s", buf); \
+        if (result >= 0) { \
+            result = jump_table.SDL_SetError("%s", str); \
+        } \
+        if (str != buf) { \
+            jump_table.SDL_free(str); \
+        } \
+        return result; \
     } \
     _static int SDLCALL SDL_sscanf##name(const char *buf, SDL_SCANF_FORMAT_STRING const char *fmt, ...) { \
         int retval; va_list ap; initcall; va_start(ap, fmt); \

src/dynapi/SDL_dynapi_overrides.h

@@ -877,3 +877,4 @@
 #define SDL_utf8strnlen SDL_utf8strnlen_REAL
 #define SDL_GDKGetTaskQueue SDL_GDKGetTaskQueue_REAL
 #define SDL_GDKRunApp SDL_GDKRunApp_REAL
+#define SDL_GetOriginalMemoryFunctions SDL_GetOriginalMemoryFunctions_REAL

src/dynapi/SDL_dynapi_procs.h

@@ -960,3 +960,4 @@ SDL_DYNAPI_PROC(size_t,SDL_utf8strnlen,(const char *a, size_t b),(a,b),return)
 SDL_DYNAPI_PROC(int,SDL_GDKGetTaskQueue,(XTaskQueueHandle *a),(a),return)
 SDL_DYNAPI_PROC(int,SDL_GDKRunApp,(SDL_main_func a, void *b),(a,b),return)
 #endif
+SDL_DYNAPI_PROC(void,SDL_GetOriginalMemoryFunctions,(SDL_malloc_func *a, SDL_calloc_func *b, SDL_realloc_func *c, SDL_free_func *d),(a,b,c,d),)