Create a 2D window and then manually focus a different window on your desktop, call SDL_PumpEvents() so the X11 driver sets its this->hidden->switch_waiting, then set a fullscreen OpenGL window (which makes the X11 driver tear down and create a new window instead of just resizing the existing one), poll for events, and the newly-created window will think it needs to pop back to a window. Fixed by resetting switch_waiting to zero if X11_CreateWindow() had to tear down a previous window.

#!/bin/sh
#
# libtool assumes that the compiler can handle the -fPIC flag
# This isn't always true (for example, nasm can't handle it)
command=""
while [ $# -gt 0 ]; do
    case "$1" in
        -?PIC)
            # Ignore -fPIC and -DPIC options
            ;;
        *)
            command="$command $1"
            ;;
    esac
    shift
done
echo $command
exec $command