As Wikipedia puts it, uClibc was mostly written from scratch,[5] but has incorporated code from glibc and other projects. I didn't bother to check in detail it

As Wikipedia puts it, uClibc was mostly written from scratch,[5] but has incorporated code from glibc and other projects. I didn't bother to check in detail it but it could mean the getaddrinfo() was taken from glibc, and later fixed, but fix not backported to glibc. Just a guess though.