gnu: lufa: Patch incompatible cast compilation error.

* gnu/packages/patches/lufa-fix-incompatible-cast.patch: New file.
* gnu/local.mk (dist_patch_DATA): Register it.
* gnu/packages/avr-xyz.scm (lufa)[source]: Use it.

3 files changed, 45 insertions, 2 deletions

diff --git a/gnu/local.mk b/gnu/local.mk
index b66ab6b2639..25ac77b706b 100644
--- a/gnu/local.mk
+++ b/gnu/local.mk
@@ -42,7 +42,7 @@
 # Copyright © 2021 Björn Höfling <bjoern.hoefling@bjoernhoefling.de>
 # Copyright © 2021 Greg Hogan <code@greghogan.com>
 # Copyright © 2021-2024 Philip McGrath <philip@philipmcgrath.com>
-# Copyright © 2021 Arun Isaac <arunisaac@systemreboot.net>
+# Copyright © 2021, 2026 Arun Isaac <arunisaac@systemreboot.net>
 # Copyright © 2021 Sharlatan Hellseher <sharlatanus@gmail.com>
 # Copyright © 2021 Dmitry Polyakov <polyakov@liltechdude.xyz>
 # Copyright © 2021 Andrew Tropin <andrew@trop.in>
@@ -1721,6 +1721,7 @@ dist_patch_DATA =						\
   %D%/packages/patches/linphone-desktop-cmake-belcard.patch	\
   %D%/packages/patches/linphone-desktop-cmake-find-modules.patch	\
   %D%/packages/patches/localed-xorg-keyboard.patch		\
+  %D%/packages/patches/lufa-fix-incompatible-cast.patch		\
   %D%/packages/patches/kaldi-ignore-failing-test.patch		\
   %D%/packages/patches/kaldi-openblas-0.3.29-compatibility.patch	\
   %D%/packages/patches/kcontacts-incorrect-country-name.patch	\
diff --git a/gnu/packages/avr-xyz.scm b/gnu/packages/avr-xyz.scm
index 0e5fff46aab..03dec7e981f 100644
--- a/gnu/packages/avr-xyz.scm
+++ b/gnu/packages/avr-xyz.scm
@@ -4,6 +4,7 @@
 ;;; Copyright © 2018 Tobias Geerinckx-Rice <me@tobias.gr>
 ;;; Copyright © 2022, 2025 Artyom V. Poptsov <poptsov.artyom@gmail.com>
 ;;; Copyright © 2023 Maxim Cournoyer <maxim@guixotic.coop>
+;;; Copyright © 2026 Arun Isaac <arunisaac@systemreboot.net>
 ;;;
 ;;; This file is part of GNU Guix.
 ;;;
@@ -123,7 +124,8 @@ multipart HEX files.")
               (file-name (git-file-name name version))
               (sha256
                (base32
-                "0ylr7qsiikcy827k18zj1vdzf0kb8hb0gjmifd75y8krkhhar49g"))))
+                "0ylr7qsiikcy827k18zj1vdzf0kb8hb0gjmifd75y8krkhhar49g"))
+              (patches (search-patches "lufa-fix-incompatible-cast.patch"))))
     (outputs '("bootloaders" "demos" "projects" "doc"))
     (build-system gnu-build-system)
     (arguments
diff --git a/gnu/packages/patches/lufa-fix-incompatible-cast.patch b/gnu/packages/patches/lufa-fix-incompatible-cast.patch
new file mode 100644
index 00000000000..81d54de43e5
--- /dev/null
+++ b/gnu/packages/patches/lufa-fix-incompatible-cast.patch
@@ -0,0 +1,40 @@
+From a13ca118d3987890b749a2a96a92f74771821f8a Mon Sep 17 00:00:00 2001
+From: Dean Camera <dean@fourwalledcubicle.com>
+Date: Sun, 30 Jun 2024 13:44:17 +1000
+Subject: [PATCH] Webserver: Fix incompatible cast warning.
+
+---
+ Projects/Webserver/Lib/DHCPServerApp.c | 6 +++---
+ 1 file changed, 3 insertions(+), 3 deletions(-)
+
+diff --git a/Projects/Webserver/Lib/DHCPServerApp.c b/Projects/Webserver/Lib/DHCPServerApp.c
+index 610d9bb6a..dfc579059 100644
+--- a/Projects/Webserver/Lib/DHCPServerApp.c
++++ b/Projects/Webserver/Lib/DHCPServerApp.c
+@@ -39,7 +39,7 @@
+ 
+ #if defined(ENABLE_DHCP_SERVER) || defined(__DOXYGEN__)
+ 
+-struct uip_conn* BroadcastConnection;
++struct uip_udp_conn* BroadcastConnection;
+ 
+ uint8_t LeasedIPs[255 / 8];
+ 
+@@ -107,7 +107,7 @@ void DHCPServerApp_Callback(void)
+ 					                                sizeof(uip_ipaddr_t), &GatewayIPAddress);
+ 
+ 				/* Send the DHCP OFFER packet */
+-				uip_poll_conn(BroadcastConnection);
++				uip_udp_periodic_conn(BroadcastConnection);
+ 				memcpy(&uip_udp_conn->ripaddr, &uip_broadcast_addr, sizeof(uip_ipaddr_t));
+ 				uip_udp_send(AppDataSize);
+ 
+@@ -135,7 +135,7 @@ void DHCPServerApp_Callback(void)
+ 				}
+ 
+ 				/* Send the DHCP ACK or NAK packet */
+-				uip_poll_conn(BroadcastConnection);
++				uip_udp_periodic_conn(BroadcastConnection);
+ 				memcpy(&uip_udp_conn->ripaddr, &uip_broadcast_addr, sizeof(uip_ipaddr_t));
+ 				uip_udp_send(AppDataSize);
+