A tiny success story.
I purchased some I2C DS1307 Real Time Clock Module for Arduino Tiny RTC from ebay $4.25 a while back and finally got around to getting it to work.
I followed the directions from http://henrysbench.capnfatz.com/henrys-bench/arduino-sensors-and-input/arduino-tiny-rtc-d1307-tutorial/ and on compile had a bunch of errors
compiler output Error linking for board Arduino Duemilanove or Diecimila w/ ATmega328 (.text+0x0)*: multiple definition of twi_readFrom Build failed for project 'rtc' twi.c.o (symbol from plugin)*: (.text+0x0): first defined here repeated a zillion times
So scratched my head for a bit, looked on the internet with no great success, swore at it, gave up and eventually came back to it and then went looking for the “multiple definition” that the compiler said I had.
Sure enough in the wire library the twi.c and twi.h exists in two places the \src and the \src\utility directory.
Renamed the \src\twi.c and twi.h to twi.c.no and twi.h.no and recompile and hey presto success, no errors, and, it runs.
Only one little issue left was that the time was wrong, I just had to force the RTC.adjust command in the source code to run and hey presto I had the correct time.