What a "word" is when talking about sizes is confusing because it's a highly overloaded term. Intel, Microsoft, and GDB are just a few vendors that have their own definition of what a "word" is. Specs that used the "wordsize" guard actually were mostly testing for the size of the C `long` fundamental type, so rename the guard for clarity. Also, get the size of `long` directly from RbConfig instead of guessing using Integer#size. Integer#size is not guaranteed to have anything to do with the `long` type.