[nostalgia/glutils] Make framebuffer default size 1x1

src/nostalgia/glutils/glutils.cpp

@@ -85,6 +85,8 @@ GLBuffer generateBuffer() noexcept {
 }
 
 FrameBuffer generateFrameBuffer(int width, int height) noexcept {
+	width = ox::max(1, width);
+	height = ox::max(1, height);
 	FrameBuffer fb;
 	fb.width = width;
 	fb.height = height;