Fixed a few warnings

src/render/SDL_render.c

@@ -3456,8 +3456,8 @@ SDL_RenderCopyExF(SDL_Renderer * renderer, SDL_Texture * texture,
         float c_minx, c_miny, c_maxx, c_maxy;
 
         const float radian_angle = (float)((M_PI * angle) / 180.0);
-        const float s = SDL_sin(radian_angle);
-        const float c = SDL_cos(radian_angle);
+        const float s = SDL_sinf(radian_angle);
+        const float c = SDL_cosf(radian_angle);
 
         minu = (float) (real_srcrect.x) / (float) texture->w;
         minv = (float) (real_srcrect.y) / (float) texture->h;

src/render/opengles/SDL_render_gles.c

@@ -769,7 +769,6 @@ static int
 GLES_RunCommandQueue(SDL_Renderer * renderer, SDL_RenderCommand *cmd, void *vertices, size_t vertsize)
 {
     GLES_RenderData *data = (GLES_RenderData *) renderer->driverdata;
-    size_t i;
 
     if (GLES_ActivateRenderer(renderer) < 0) {
         return -1;