diff --git a/configure b/configure
index 8c97ca5fb..a2902e6c6 100755
--- a/configure
+++ b/configure
@@ -378,7 +378,11 @@ code=
 int main(void)
 {
 	gzFile f = gzopen("/dev/null", "wb");
-	return f != NULL ? 0 : 1;
+	if (f != NULL) {
+		gzclose(f);
+		return 0;
+	}
+	return 1;
 }
 /*END*/
 var=HAVE_GOOD_LIBSODIUM