diff -urB avrdude-6.3/linuxgpio.c avrdude-6.3-patched/linuxgpio.c
--- avrdude-6.3/linuxgpio.c	2016-02-15 23:16:32.000000000 +0300
+++ avrdude-6.3-patched/linuxgpio.c	2016-10-10 00:59:28.000000000 +0300
@@ -66,7 +66,7 @@
     return fd;
   }
 
-  len = snprintf(buf, sizeof(buf), "%ud", gpio);
+  len = snprintf(buf, sizeof(buf), "%u", gpio);
   r = write(fd, buf, len);
   close(fd);
 
@@ -84,7 +84,7 @@
     return fd;
   }
 
-  len = snprintf(buf, sizeof(buf), "%ud", gpio);
+  len = snprintf(buf, sizeof(buf), "%u", gpio);
   r = write(fd, buf, len);
   close(fd);
 
@@ -95,7 +95,7 @@
 {
   char filepath[60];
 
-  snprintf(filepath, sizeof(filepath), "/sys/class/gpio/gpio%ud/value", gpio);
+  snprintf(filepath, sizeof(filepath), "/sys/class/gpio/gpio%u/value", gpio);
   return (open(filepath, O_RDWR));
 }
 
@@ -104,7 +104,7 @@
   int fd, r;
   char buf[60];
 
-  snprintf(buf, sizeof(buf), "/sys/class/gpio/gpio%ud/direction", gpio);
+  snprintf(buf, sizeof(buf), "/sys/class/gpio/gpio%u/direction", gpio);
 
   fd = open(buf, O_WRONLY);
   if (fd < 0) {