diff --git a/libasn1compiler/asn1c_misc.c b/libasn1compiler/asn1c_misc.c
index b464b64..257e02c 100644
--- a/libasn1compiler/asn1c_misc.c
+++ b/libasn1compiler/asn1c_misc.c
@@ -94,6 +94,8 @@
 	FILE *fp;
 	int fd;
 
+	(void)arg;	/* Unused argument */
+
 	/*
 	 * Compute filenames.
 	 */