txt2ast(): Mark iovec structure as const.

The function does not modify the fields of "tx".

diff --git a/tfortune.c b/tfortune.c
index e5b2061f22f5d537e14f5e8282013c042aa301f6..7e59eb69e39c2872d715ce5f0aff71fb65c06011 100644 (file)
--- a/tfortune.c
+++ b/tfortune.c
@@ -216,7 +216,7 @@ static int read_tag_expression(struct iovec *result)
        return ret;
 }
 
-static int tx2ast(struct iovec *tx, struct txp_context **ast)
+static int tx2ast(const struct iovec *tx, struct txp_context **ast)
 {
        int ret;
        char *errmsg;