diff --git a/ax25-tools-mkiss_fix.patch b/ax25-tools-mkiss_fix.patch
new file mode 100644
index 0000000..1ce9251
--- /dev/null
+++ b/ax25-tools-mkiss_fix.patch
@@ -0,0 +1,62 @@
+--- a/kiss/kissattach.c
++++ b/kiss/kissattach.c
+@@ -1,5 +1,6 @@
++#define _DEFAULT_SOURCE
++#define _XOPEN_SOURCE 500
+ #include <stdio.h>
+-#define __USE_XOPEN
+ #include <stdlib.h>
+ #include <string.h>
+ #include <unistd.h>
+--- a/kiss/kissnetd.c
++++ b/kiss/kissnetd.c
+@@ -9,8 +9,9 @@
+  * F1OAT 960804 - Frederic RIBLE
+  */
+  
++#define _DEFAULT_SOURCE
++#define _XOPEN_SOURCE 500
+ #include <stdio.h>
+-#define __USE_XOPEN
+ #include <stdlib.h>
+ #include <sys/time.h>
+ #include <sys/types.h>
+--- a/kiss/mkiss.c
++++ :b/kiss/mkiss.c
+@@ -37,8 +37,9 @@
+  * 1.08 xx/xx/99 Tom Mazouch - Adjustable poll interval
+  */
+ 
++#define _DEFAULT_SOURCE
++#define _XOPEN_SOURCE 500
+ #include <stdio.h>
+-#define __USE_XOPEN
+ #include <string.h>
+ #include <errno.h>
+ #include <stdlib.h>
+--- a/kiss/net2kiss.c
++++ b/kiss/net2kiss.c
+@@ -30,8 +30,9 @@
+ 
+ /*****************************************************************************/
+ 
++#define _DEFAULT_SOURCE
++#define _XOPEN_SOURCE 500
+ #include <stdio.h>
+-#define __USE_XOPEN
+ #include <stdlib.h>
+ #include <sys/types.h>
+ #include <sys/time.h>
+--- a/6pack/m6pack.c
++++ b/6pack/m6pack.c
+@@ -33,8 +33,9 @@
+  *********************************************************************
+  */
+ 
++#define _DEFAULT_SOURCE
++#define _XOPEN_SOURCE 500
+ #include <stdio.h>
+-#define __USE_XOPEN
+ #include <string.h>
+ #include <errno.h>
+ #include <stdlib.h>