I now repeat myself:
Don't call the CreateBullet() function if it doesn't exist.
Either create a way for each library to check if another library is present (and if not, then don't call upon those libraries),
or
seperate the CreateBullet() part from the player library and just have the player library return an event to the main program stating that the fire button was pressed. Then the main program can decide whether or not to actually call upon the bullet library.
If I am not answering your question, then I do not understand the problem.
Don't call the CreateBullet() function if it doesn't exist.
Either create a way for each library to check if another library is present (and if not, then don't call upon those libraries),
or
seperate the CreateBullet() part from the player library and just have the player library return an event to the main program stating that the fire button was pressed. Then the main program can decide whether or not to actually call upon the bullet library.
If I am not answering your question, then I do not understand the problem.