Handle xwayland configures

[flaviozavan]

Explicitly handle xwayland configures. This fixes issues seen in darktable and prusa-slicer, where surfaces would never be mapped

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To test, try running prusa-slicer or darktable without the proposed changes. Darktable never maps a single surface, while prusa-slicer will only map the splash screen. Apply changes, and they both should work as expected.

[inclement]

Thanks - surprised I've never hit this, but I guess it must just be a few apps that depend on it and I happen to not use them.