Fix displayed color/depth/stencil bits values

The values passed to SDL are just the minimum required. Get actually
values of colorbits, depthbits, and stencilbits from SDL instead of
assuming that the engine got exactly what it asked for.

code/sdl/sdl_glimp.c

@@ -451,6 +451,7 @@ static int GLimp_SetMode(int mode, qboolean fullscreen, qboolean noborder, qbool
 	for (i = 0; i < 16; i++)
 	{
 		int testColorBits, testDepthBits, testStencilBits;
+		int realColorBits[3];
 
 		// 0 - default
 		// 1 - minus colorBits
@@ -664,9 +665,13 @@ static int GLimp_SetMode(int mode, qboolean fullscreen, qboolean noborder, qbool
 			ri.Printf( PRINT_DEVELOPER, "SDL_GL_SetSwapInterval failed: %s\n", SDL_GetError( ) );
 		}
 
-		glConfig.colorBits = testColorBits;
-		glConfig.depthBits = testDepthBits;
-		glConfig.stencilBits = testStencilBits;
+		SDL_GL_GetAttribute( SDL_GL_RED_SIZE, &realColorBits[0] );
+		SDL_GL_GetAttribute( SDL_GL_GREEN_SIZE, &realColorBits[1] );
+		SDL_GL_GetAttribute( SDL_GL_BLUE_SIZE, &realColorBits[2] );
+		SDL_GL_GetAttribute( SDL_GL_DEPTH_SIZE, &glConfig.depthBits );
+		SDL_GL_GetAttribute( SDL_GL_STENCIL_SIZE, &glConfig.stencilBits );
+
+		glConfig.colorBits = realColorBits[0] + realColorBits[1] + realColorBits[2];
 
 		ri.Printf( PRINT_ALL, "Using %d color bits, %d depth, %d stencil display.\n",
 				glConfig.colorBits, glConfig.depthBits, glConfig.stencilBits );