Bug #15327: configure: --with-tcp-port option being partially ignored

make sure that if builder configured with a non-standard (!= 3306)
default TCP port that value actually gets used throughout. if they
didn't configure a value, assume "use a sensible default", which
will be read from /etc/services or, failing that, from the factory
default. That makes the order of preference
- command-line option
- my.cnf, where applicable
- $MYSQL_TCP_PORT environment variable
- /etc/services (unless configured --with-tcp-port)
- default port (--with-tcp-port=... or factory default)

scripts/mysql_fix_privilege_tables.sh

@@ -25,6 +25,7 @@ sql_only=0
 basedir="@prefix@"
 verbose=0
 args=""
+# no elaborate fallback here; with no argument, it will happen in "mysql"
 port=""
 socket=""
 database="mysql"