Comment by MathMonkeyMan

I've heard something along the lines of "the standard is to define facilities that will be used in most programs, and to codify widespread existing practice." That was in the context of "I don't like this proposed feature," though. This was for C++, not C.

A lot of stuff in the C++11 standard library was based on widespread use of Boost. Since then, I don't know. Also, were things like templates and lambdas implemented as compiler extensions before standardization? I don't know, but I doubt it. Maybe "we're a committee of people who will decide on a thing and we hope you like it" was always the norm in many ways.