[account42]

> There is also the mangle-use-repair choice.

Which is problematic for thread safety and depending on the source of the string (constant) may not be possible.

[souprock]

It's not problematic. C programmers are expected to avoid screwing that up. C is a full-power language.

If available, strdupa() would be a fine way to get a suitable local copy of the string. Commonly though, the programmer knows that there will not be threads and can make the string non-constant.