1 files changed, 5 insertions, 0 deletions
diff --git a/lib/sm3.h b/lib/sm3.h
index 4ca7f7a103..28af4dff1c 100644
--- a/lib/sm3.h
+++ b/lib/sm3.h
@@ -27,6 +27,11 @@
 #ifndef SM3_H
 # define SM3_H 1
 
+/* This file uses HAVE_OPENSSL_SM3.  */
+# if !_GL_CONFIG_H_INCLUDED
+#  error "Please include config.h first."
+# endif
+
 # include <stdio.h>
 # include <stdint.h>