TL;DR version: some software vendors used memcpy instead of memmove when copying memory contents in overlapping blocks and that used to work until recent change

TL;DR version: some software vendors used memcpy instead of memmove when copying memory contents in overlapping blocks and that used to work until recent change in glibc. Torvalds insists that glibc should try to maintain compatibility. Drepper says that programs should be fixed. I tend to side with Drepper on this one, but what is HN's take?