Add missing implementation for SYMBOL and NO_SYMBOL messages

[P1cheneG]

This is a fix for #8505. In the fix, I added the missing message to the exported one. Previously, the program displayed the error: "unknown ISC error 336067776", Now the program outputs: "Function TEST_FUNC already exists". The original problem was reproduced in Windows

[AlexPeshkoff]

Instead this changes you should simply have firebird.msg available.

[P1cheneG]

Hello. Thank you for the answer, but the other messages are working fine. In my opinion, either all messages should require the firebird.msg file, or none of them should. There is an example of error output for creating a function and a syntax error:

SQL CODE = 335544351
unsuccessful metadata update
CREATE FUNCTION TEST_FUNC failed
unknown ISC error 336068876
SQL CODE = 335544569
Dynamic SQL Error
SQL error code = -104
Token unknown - line 1, column 1
creat

Using this code:

att->execute(&status, tra, 0,
    "create function TEST_FUNC RETURNS float as BEGIN RETURN 1; END;",
    3, NULL, NULL, NULL, NULL);
att->execute(&status, tra, 0,
    "creat function TEST_FUNC RETURNS float as BEGIN RETURN 1; END;",
    3, NULL, NULL, NULL, NULL);

[AlexPeshkoff]

No idea why some messages were put directly to client library. That's historically so since interbase times.