diff -Nru xsystem35-1.7.3-pre5/debian/changelog xsystem35-1.7.3-pre5/debian/changelog
--- xsystem35-1.7.3-pre5/debian/changelog	2024-03-08 08:18:56.000000000 +0000
+++ xsystem35-1.7.3-pre5/debian/changelog	2024-03-31 19:59:19.000000000 +0000
@@ -1,8 +1,10 @@
-xsystem35 (1.7.3-pre5-10build1) noble; urgency=medium
+xsystem35 (1.7.3-pre5-11) unstable; urgency=low
 
-  * No-change rebuild against libglib2.0-0t64
+  * Fix FTBFS by -Werror=implicit-function-declaration (Closes: #1066527)
+    - Add debian/patches/05_fix_ftbfs_implicit-function-declaration.patch
+  * debian/control: pkg-config -> pkgconf
 
- -- Steve Langasek <steve.langasek@ubuntu.com>  Fri, 08 Mar 2024 08:18:56 +0000
+ -- Ying-Chun Liu (PaulLiu) <paulliu@debian.org>  Mon, 01 Apr 2024 03:59:19 +0800
 
 xsystem35 (1.7.3-pre5-10) unstable; urgency=low
 
diff -Nru xsystem35-1.7.3-pre5/debian/control xsystem35-1.7.3-pre5/debian/control
--- xsystem35-1.7.3-pre5/debian/control	2024-03-08 08:18:56.000000000 +0000
+++ xsystem35-1.7.3-pre5/debian/control	2024-03-31 19:59:14.000000000 +0000
@@ -1,8 +1,7 @@
 Source: xsystem35
 Section: games
 Priority: optional
-Maintainer: Ubuntu Developers <ubuntu-devel-discuss@lists.ubuntu.com>
-XSBC-Original-Maintainer: Ying-Chun Liu (PaulLiu) <paulliu@debian.org>
+Maintainer: Ying-Chun Liu (PaulLiu) <paulliu@debian.org>
 Build-Depends: autopoint,
                chrpath,
                debhelper-compat (= 12),
@@ -13,7 +12,7 @@
                libltdl-dev,
                libpulse-dev,
                libvorbis-dev,
-               pkg-config,
+               pkgconf,
                xsltproc
 Standards-Version: 4.4.1
 Homepage: http://8ne.sakura.ne.jp:20008/chika/unitbase/xsys35/
diff -Nru xsystem35-1.7.3-pre5/debian/patches/05_fix_ftbfs_implicit-function-declaration.patch xsystem35-1.7.3-pre5/debian/patches/05_fix_ftbfs_implicit-function-declaration.patch
--- xsystem35-1.7.3-pre5/debian/patches/05_fix_ftbfs_implicit-function-declaration.patch	1970-01-01 00:00:00.000000000 +0000
+++ xsystem35-1.7.3-pre5/debian/patches/05_fix_ftbfs_implicit-function-declaration.patch	2024-03-31 19:45:38.000000000 +0000
@@ -0,0 +1,41 @@
+Description: Fix FTBFS caused by -Werror=implicit-function-declaration
+Bug-Debian: http://bugs.debian.org/1066527
+Author: Ying-Chun Liu (PaulLiu) <paulliu@debian.org>
+Last-Update: 2024-04-01
+Index: xsystem35-1.7.3-pre5/modules/NIGHTDLL/sactcg.c
+===================================================================
+--- xsystem35-1.7.3-pre5.orig/modules/NIGHTDLL/sactcg.c
++++ xsystem35-1.7.3-pre5/modules/NIGHTDLL/sactcg.c
+@@ -35,6 +35,7 @@
+ #include "surface.h"
+ #include "ngraph.h"
+ #include "sactcg.h"
++#include "eucsjis.h"
+ 
+ #define CGMAX 65536
+ static cginfo_t *cgs[CGMAX];
+Index: xsystem35-1.7.3-pre5/modules/NIGHTDLL/nt_msg.c
+===================================================================
+--- xsystem35-1.7.3-pre5.orig/modules/NIGHTDLL/nt_msg.c
++++ xsystem35-1.7.3-pre5/modules/NIGHTDLL/nt_msg.c
+@@ -18,6 +18,7 @@
+ #include "sactcg.h"
+ #include "sjisname.h"
+ #include "sactstring.h"
++#include "eucsjis.h"
+ 
+ 
+ extern int ntsel_dosel(void);
+Index: xsystem35-1.7.3-pre5/modules/NIGHTDLL/nt_event.c
+===================================================================
+--- xsystem35-1.7.3-pre5.orig/modules/NIGHTDLL/nt_event.c
++++ xsystem35-1.7.3-pre5/modules/NIGHTDLL/nt_event.c
+@@ -13,6 +13,8 @@
+ #include "night.h"
+ #include "sprite.h"
+ 
++extern void cb_waitkey_sprite(agsevent_t *e);
++
+ /*
+   Messageキー入力待ち時の
+ */
diff -Nru xsystem35-1.7.3-pre5/debian/patches/series xsystem35-1.7.3-pre5/debian/patches/series
--- xsystem35-1.7.3-pre5/debian/patches/series	2019-11-27 18:00:18.000000000 +0000
+++ xsystem35-1.7.3-pre5/debian/patches/series	2024-03-31 19:10:48.000000000 +0000
@@ -4,3 +4,4 @@
 03_remove_libltdl.patch
 04_esd_to_pulseaudio.patch
 04_sndcnv_64bit.patch
+05_fix_ftbfs_implicit-function-declaration.patch