After long time I started working with my gamemode and tried to compile my gamemode "sampctl package build".
After that it updated dependencies and indirection.inc was added, but it gives ...dependencies\indirection\indirection.inc:940 (error) undefined symbol "Indirection_OnGameModeInit".
What may cause the problem and how should it be fixed?

Do you have an extra "forward" somewhere in your code for "OnGameModeInit"?