Render targets are a core feature of SDL 3.0, so this flag has been removed.
The OpenGL ES renderer still doesn't support them, but we'll deal with that later.
Fixes https://github.com/libsdl-org/SDL/issues/8059
Simple DirectMedia Layer is a cross-platform development library designed
to provide low level access to audio, keyboard, mouse, joystick, and graphics
hardware via OpenGL and Direct3D. It is used by video playback software,
emulators, and popular games including Valve's award winning catalog
and many Humble Bundle games.
More extensive documentation is available in the docs directory, starting
with README.md