[mikeash]

I'd wager that many of these errors predate many of the commenters on this site. X is pretty old.

[MostAwesomeDude]

I was an X.org hacker a few years ago. X predates me.

X is (very) roughly the size of GCC. It's massive and it's nearly entirely C, with a few modern Python scripts to generate some of the more onerous tables. There are many old libraries, and they are horrifying. Eldritch, cyclopean, etc.

[rjsw]

A lot of the libraries listed are relatively new though.

[jevinskie]

An macros to rival, but not beat (they can't be!!!) Perl's!