diff --git a/lapack-netlib/SRC/iparam2stage.c b/lapack-netlib/SRC/iparam2stage.c
index 87c624d65..1b6c4c8b8 100644
--- a/lapack-netlib/SRC/iparam2stage.c
+++ b/lapack-netlib/SRC/iparam2stage.c
@@ -2,6 +2,7 @@
 #include <stdlib.h>
 #include <string.h>
 #include <stdio.h>
+#include <ctype.h>
 #include <complex.h>
 #ifdef complex
 #undef complex