Added SDL_strnstr()

src/dynapi/SDL_dynapi.sym

@@ -960,6 +960,8 @@ SDL3_0.0.0 {
     SDL_GetGamepadMappings;
     SDL_GetTouchDevices;
     SDL_GetTouchDeviceName;
+    SDL_strnstr;
+    SDL_wcsnstr;
     # extra symbols go here (don't modify this line)
   local: *;
 };

src/dynapi/SDL_dynapi_overrides.h

@@ -985,3 +985,5 @@
 #define SDL_GetGamepadMappings SDL_GetGamepadMappings_REAL
 #define SDL_GetTouchDevices SDL_GetTouchDevices_REAL
 #define SDL_GetTouchDeviceName SDL_GetTouchDeviceName_REAL
+#define SDL_strnstr SDL_strnstr_REAL
+#define SDL_wcsnstr SDL_wcsnstr_REAL

src/dynapi/SDL_dynapi_procs.h

@@ -1010,3 +1010,5 @@ SDL_DYNAPI_PROC(SDL_Renderer*,SDL_CreateRendererWithProperties,(SDL_PropertiesID
 SDL_DYNAPI_PROC(char**,SDL_GetGamepadMappings,(int *a),(a),return)
 SDL_DYNAPI_PROC(SDL_TouchID*,SDL_GetTouchDevices,(int *a),(a),return)
 SDL_DYNAPI_PROC(const char*,SDL_GetTouchDeviceName,(SDL_TouchID a),(a),return)
+SDL_DYNAPI_PROC(char*,SDL_strnstr,(const char *a, const char *b, size_t c),(a,b,c),return)
+SDL_DYNAPI_PROC(wchar_t*,SDL_wcsnstr,(const wchar_t *a, const wchar_t *b, size_t c),(a,b,c),return)