diff --git a/lib/roken/esetenv.c b/lib/roken/esetenv.c
index 4f601a72f..66b6607ce 100644
--- a/lib/roken/esetenv.c
+++ b/lib/roken/esetenv.c
@@ -43,6 +43,6 @@ RCSID("$Id$");
 void
 esetenv(const char *var, const char *val, int rewrite)
 {
-    if (setenv ((char *)var, val, rewrite))
+    if (setenv ((char *)var, (char *)val, rewrite))
 	errx (1, "failed setting environment variable %s", var);
 }