>NSS has been blessed as the standard SSL library for LSB.
Being part of some standard won't magically proliferate it.
$ for i in mozilla-nss libgnutls26 libopenssl1_0_0; do rpm --test -e "$i" 2>&1 | pcregrep -o '(?<=\(installed\) )\S+' | sort -u | wc -l; done
..I still wait for the day until a "beautiful" API comes around. One that does not hide pointers behind, or use, typedefs, but rather ptrs to <incomplete> structs, does so in lower-case, and also has a prefix of sorts. No library fulfills all of these atm.