Completion of error handling

[elfring]

Would you like to add more error handling for return values from functions like the following?

• ftell ⇒ readTagLineRaw
• printf ⇒ printField

[masatake]

I wonder what ctags should do when printf is failed. Printing a message to stderr via fprintf and exiting are enough?

[masatake]

What we can do now may be just aborting. However, it is not good for a tool using ctags as a library like Geany. If we introduce a context oriented memory manager, we can report the error to the caller context (of a client tool).