[a1o]

> Considering that a C program with an empty main function is 6kB on this system, {fmt} now adds less than 10kB to the binary.

Interesting, I've never done this test!

[JonChesterfield]

It varies widely with whether the C library is dynamically or statically linked and with how the application (and C library) were built. And on which C library it is. Also a little on whether you're using elf or some other container.