Regression with SDL (or mesa?) with xwayland

After a recent update, colors in SDL are all scrambled. On left, the Anbox splash screen, displayed with SDL; on right, QEMU using the SDL backend (showing Mate's file manager). On the other hand, the Android applications in Anbox work fine, as that part of Anbox only uses SDL to get an EGL display+surface.

I have witnessed the issue on Weston+XWayland emulated in QEMU and in Sway+XWayland. The former appears to use the mesa-dri-gallium directly (I can check if someone give me instructions) while the latter uses the mesa-dri-intel driver. I have not seen the issue on i3 or using the Wayland backend, so it appears XWayland-specific.