diff --git a/build/rmkdepend/ifparser.c b/build/rmkdepend/ifparser.c
index 8ad871630b73b397df1e9fcb7b0b878fd64d5fab..2f5de32a5436ba8dd7dc6a9fde363c9d4f2140ae 100644
--- a/build/rmkdepend/ifparser.c
+++ b/build/rmkdepend/ifparser.c
@@ -62,10 +62,9 @@
 
 #include "ifparser.h"
 #include <ctype.h>
+#include <stdlib.h>
 #include <string.h>
 
-extern long strtol(const char *nptr, char **endptr, int base);
-
 /****************************************************************************
      Internal Macros and Utilities for Parser
  ****************************************************************************/