Updated SDL and fixed Emscripten build

conan/sdl/all/test_package/test_package.cpp

@@ -0,0 +1,9 @@
+#include <SDL.h>
+#include <iostream>
+
+int main(int argc, char* args[]) {
+    SDL_version v;
+    SDL_GetVersion(&v);
+    std::cout << "SDL version " << int(v.major) << "." << int(v.minor) << "." << int(v.patch) << std::endl;
+    return 0;
+}