diff -u xserver-xorg-video-dummy-0.4.0/debian/changelog xserver-xorg-video-dummy-0.4.0/debian/changelog
--- xserver-xorg-video-dummy-0.4.0/debian/changelog
+++ xserver-xorg-video-dummy-0.4.0/debian/changelog
@@ -1,3 +1,17 @@
+xserver-xorg-video-dummy (1:0.4.0-1.1) unstable; urgency=medium
+
+  * Non-maintainer upload.
+  * Fix FTBFS with GCC 15 / C23 (Closes: #1098167):
+    src/dummy.h: list the WindowPtr argument type in the dummyRec
+    CreateWindow function pointer declaration. Under C23, an empty
+    parameter list '()' is equivalent to '(void)', so the original
+    declaration is incompatible with the CreateWindowProcPtr assigned
+    to it in dummy_driver.c.
+    Backport of upstream commit 234cb0271bbf69ef3bd0b90a2efdd8fb724b78f0
+    by Alan Coopersmith, released in xf86-video-dummy 0.4.1.
+
+ -- Azeez Syed <azeezalishah@gmail.com>  Sat, 23 May 2026 15:30:00 +0530
+
 xserver-xorg-video-dummy (1:0.4.0-1) unstable; urgency=medium
 
   * New upstream release.
only in patch2:
unchanged:
--- xserver-xorg-video-dummy-0.4.0.orig/src/dummy.h
+++ xserver-xorg-video-dummy-0.4.0/src/dummy.h
@@ -52,7 +52,7 @@
     int cursorFG, cursorBG;
 
     dummy_colors colors[1024];
-    Bool        (*CreateWindow)() ;     /* wrapped CreateWindow */
+    Bool        (*CreateWindow)(WindowPtr) ;     /* wrapped CreateWindow */
     Bool prop;
     /* XRANDR support begin */
     int num_screens;