> My point is that users are being held hostage so that the glibc maintainers can say "meh, those stupid programmers at <wherever> should read the C99 standard".
This was specified already in ANSI-C in 80's, i.e. last century.
Memory debugging tools like Valgrind, duma etc. have been giving warnings about memcpy() calls with overlapping addresses at least for a decade.
If 10-20 years isn't enough for e.g. Adobe to test with freely available (or commercial) tools that their software is robust, portable and correctly implemented, I don't have very high hopes of it ever being what I (and apparently Steve Jobs) call "product quality" SW.