diff --git a/interfaces.c b/interfaces.c
index 7895c3291..34f07770b 100644
--- a/interfaces.c
+++ b/interfaces.c
@@ -52,6 +52,14 @@ struct rtentry;
 # include <sys/sockio.h>
 #endif
 #include <stdio.h>
+#ifdef STDC_HEADERS
+# include <stdlib.h>
+# include <stddef.h>
+#else
+# ifdef HAVE_STDLIB_H
+#  include <stdlib.h>
+# endif
+#endif /* STDC_HEADERS */
 #ifdef HAVE_STRING_H
 # if defined(HAVE_MEMORY_H) && !defined(STDC_HEADERS)
 #  include <memory.h>