diff --git a/debian/compiz-fusion-plugins-main-trinity/compiz-fusion-plugins-main-trinity-0.8.4/debian/changelog b/debian/compiz-fusion-plugins-main-trinity/compiz-fusion-plugins-main-trinity-0.8.4/debian/changelog
index ee8866a9..7e4db77f 100644
--- a/debian/compiz-fusion-plugins-main-trinity/compiz-fusion-plugins-main-trinity-0.8.4/debian/changelog
+++ b/debian/compiz-fusion-plugins-main-trinity/compiz-fusion-plugins-main-trinity-0.8.4/debian/changelog
@@ -1,3 +1,9 @@
+compiz-fusion-plugins-main-trinity (0.8.4-3debian13.0.0+7~a) trixie; urgency=low
+
+  * Fix implicit declaration for malloc and free that cause FTBFS.
+
+ -- Slávek Banko <slavek.banko@axis.cz>  Sun, 22 Sep 2023 15:20:05 +0200
+
 compiz-fusion-plugins-main-trinity (0.8.4-3debian13.0.0+6~a) trixie; urgency=low
 
   * Build without support for gconf.
diff --git a/debian/compiz-fusion-plugins-main-trinity/compiz-fusion-plugins-main-trinity-0.8.4/debian/patches/11-malloc-free-implicit-declaration.diff b/debian/compiz-fusion-plugins-main-trinity/compiz-fusion-plugins-main-trinity-0.8.4/debian/patches/11-malloc-free-implicit-declaration.diff
new file mode 100644
index 00000000..92eaffc4
--- /dev/null
+++ b/debian/compiz-fusion-plugins-main-trinity/compiz-fusion-plugins-main-trinity-0.8.4/debian/patches/11-malloc-free-implicit-declaration.diff
@@ -0,0 +1,97 @@
+Index: compiz-fusion-plugins-main-trinity-0.8.4/src/mag/mag.c
+===================================================================
+--- compiz-fusion-plugins-main-trinity-0.8.4.orig/src/mag/mag.c
++++ compiz-fusion-plugins-main-trinity-0.8.4/src/mag/mag.c
+@@ -21,6 +21,7 @@
+  */
+ 
+ #include <math.h>
++#include <stdlib.h>
+ #include <string.h>
+ 
+ #include <compiz-core.h>
+Index: compiz-fusion-plugins-main-trinity-0.8.4/src/mousepoll/mousepoll.c
+===================================================================
+--- compiz-fusion-plugins-main-trinity-0.8.4.orig/src/mousepoll/mousepoll.c
++++ compiz-fusion-plugins-main-trinity-0.8.4/src/mousepoll/mousepoll.c
+@@ -20,6 +20,7 @@
+  *
+  */
+ 
++#include <stdlib.h>
+ #include <compiz-core.h>
+ 
+ #include "compiz-mousepoll.h"
+Index: compiz-fusion-plugins-main-trinity-0.8.4/src/opacify/opacify.c
+===================================================================
+--- compiz-fusion-plugins-main-trinity-0.8.4.orig/src/opacify/opacify.c
++++ compiz-fusion-plugins-main-trinity-0.8.4/src/opacify/opacify.c
+@@ -21,6 +21,7 @@
+  *
+  */
+ 
++#include <stdlib.h>
+ #include <compiz-core.h>
+ #include "opacify_options.h"
+ 
+Index: compiz-fusion-plugins-main-trinity-0.8.4/src/scaleaddon/scaleaddon.c
+===================================================================
+--- compiz-fusion-plugins-main-trinity-0.8.4.orig/src/scaleaddon/scaleaddon.c
++++ compiz-fusion-plugins-main-trinity-0.8.4/src/scaleaddon/scaleaddon.c
+@@ -25,6 +25,7 @@
+  */
+ 
+ #include <math.h>
++#include <stdlib.h>
+ #include <string.h>
+ #include <X11/Xatom.h>
+ 
+Index: compiz-fusion-plugins-main-trinity-0.8.4/src/session/session.c
+===================================================================
+--- compiz-fusion-plugins-main-trinity-0.8.4.orig/src/session/session.c
++++ compiz-fusion-plugins-main-trinity-0.8.4/src/session/session.c
+@@ -29,6 +29,7 @@
+ 
+ #include <compiz-core.h>
+ 
++#include <stdlib.h>
+ #include <string.h>
+ #include <errno.h>
+ #include <pwd.h>
+Index: compiz-fusion-plugins-main-trinity-0.8.4/src/vpswitch/vpswitch.c
+===================================================================
+--- compiz-fusion-plugins-main-trinity-0.8.4.orig/src/vpswitch/vpswitch.c
++++ compiz-fusion-plugins-main-trinity-0.8.4/src/vpswitch/vpswitch.c
+@@ -27,6 +27,7 @@
+  */
+ 
+ #include <compiz-core.h>
++#include <stdlib.h>
+ #include <string.h>
+ #include <X11/keysymdef.h>
+ #include "vpswitch_options.h"
+Index: compiz-fusion-plugins-main-trinity-0.8.4/src/winrules/winrules.c
+===================================================================
+--- compiz-fusion-plugins-main-trinity-0.8.4.orig/src/winrules/winrules.c
++++ compiz-fusion-plugins-main-trinity-0.8.4/src/winrules/winrules.c
+@@ -20,7 +20,7 @@
+  */
+ 
+ #include <compiz-core.h>
+-
++#include <stdlib.h>
+ #include <X11/Xatom.h>
+ 
+ #define WINRULES_SCREEN_OPTION_SKIPTASKBAR_MATCH  0
+Index: compiz-fusion-plugins-main-trinity-0.8.4/src/workarounds/workarounds.c
+===================================================================
+--- compiz-fusion-plugins-main-trinity-0.8.4.orig/src/workarounds/workarounds.c
++++ compiz-fusion-plugins-main-trinity-0.8.4/src/workarounds/workarounds.c
+@@ -20,6 +20,7 @@
+  * This plug-in for Metacity-like workarounds.
+  */
+ 
++#include <stdlib.h>
+ #include <string.h>
+ #include <limits.h>
+ 
diff --git a/debian/compiz-fusion-plugins-main-trinity/compiz-fusion-plugins-main-trinity-0.8.4/debian/patches/series b/debian/compiz-fusion-plugins-main-trinity/compiz-fusion-plugins-main-trinity-0.8.4/debian/patches/series
index 229ab27f..5a691915 100644
--- a/debian/compiz-fusion-plugins-main-trinity/compiz-fusion-plugins-main-trinity-0.8.4/debian/patches/series
+++ b/debian/compiz-fusion-plugins-main-trinity/compiz-fusion-plugins-main-trinity-0.8.4/debian/patches/series
@@ -5,3 +5,4 @@
 08_disable_desktop_vpswitch.patch
 09-multiple-definitions.diff
 10-disable-gconf.patch
+11-malloc-free-implicit-declaration.diff