Bug#1098167: xserver-xorg-video-dummy: ftbfs with GCC-15

Control: tags -1 + patch

Attached debdiff for an NMU (xserver-xorg-video-dummy 1:0.4.0-1.1)
fixing the GCC 15 / C23 FTBFS.

The fix is a one-line backport of upstream commit
234cb0271bbf69ef3bd0b90a2efdd8fb724b78f0 by Alan Coopersmith, released
in xf86-video-dummy 0.4.1: src/dummy.h declares the dummyRec
CreateWindow function pointer with explicit (WindowPtr) argument
instead of empty (), which under C23 means (void) and conflicts with
the CreateWindowProcPtr assigned to it in dummy_driver.c.

Built cleanly in a sid amd64 sbuild chroot. The lintian
'no-human-maintainers' error is pre-existing (the Maintainer field is
identical in 0.4.0-1).

Not a DD - posted for sponsor review.

Regards,
 Azeez Syed