diff --git a/src/conky.h b/src/conky.h
index e132fd87..4e09420f 100644
--- a/src/conky.h
+++ b/src/conky.h
@@ -31,6 +31,8 @@
 #ifndef _conky_h_
 #define _conky_h_
 
+#define __STDC_FORMAT_MACROS
+
 #include <config.h>	/* defines */
 #include "common.h"	/* at least for struct dns_data */
 #include <sys/utsname.h> /* struct uname_s */