There is an area around 2.4.36.5 where the fall and rise of "fuck" and "shit" closely resemble each other. I'm guessing it's a macro which concatenates the two expletives for use in the code.
That's what I'm thinking, they used the ## preprocessor operator to stick "fuck" and "shit". Oh, if this is linux, then the identifier is more likely to be "fuck_shit".