use const-correct types with strchr, strstr, etc.

common/wireaddr.c

@@ -291,10 +291,10 @@ char *fmt_wireaddr(const tal_t *ctx, const struct wireaddr *a)
 bool separate_address_and_port(const tal_t *ctx, const char *arg,
 			       char **addr, u16 *port)
 {
-	char *portcolon;
+	const char *portcolon;
 
 	if (strstarts(arg, "[")) {
-		char *end = strchr(arg, ']');
+		const char *end = strchr(arg, ']');
 		if (!end)
 			return false;
 		/* Copy inside [] */

connectd/tor_autoservice.c

@@ -201,7 +201,7 @@ static void negotiate_auth(struct rbuf *rbuf, const char *tor_password)
 	tor_send_cmd(rbuf, "PROTOCOLINFO 1");
 
 	while ((line = tor_response_line(rbuf)) != NULL) {
-		const char *p;
+		char *p;
 
 		if (!strstarts(line, "AUTH METHODS="))
 			continue;

db/db_sqlite3.c

@@ -464,8 +464,8 @@ static char **prepare_table_manip(const tal_t *ctx,
 				  struct db *db, const char *tablename)
 {
 	sqlite3_stmt *stmt;
-	const char *sql;
-	char *cmd, *bracket;
+	const char *sql, *bracket;
+	char *cmd;
 	char **parts;
 	int err;
 	struct db_sqlite3 *wrapper = (struct db_sqlite3 *)db->conn;

devtools/check-bolt.c

@@ -236,7 +236,7 @@ static void fail_mismatch(const char *filename,
 static bool find_strings(const char *bolttext, char **strings, size_t nstrings)
 {
 	const char *p = bolttext;
-	char *find;
+	const char *find;
 
 	if (nstrings == 0)
 		return true;

plugins/spender/multifundchannel.c

@@ -1846,7 +1846,7 @@ param_destinations_array(struct command *cmd, const char *name,
 	json_for_each_arr(i, json_dest, tok) {
 		struct multifundchannel_destination *dest;
 		const char *id;
-		char *addrhint;
+		const char *addrhint;
 		struct amount_sat *amount, *request_amt;
 		bool *announce;
 		struct amount_msat *push_msat;