My Arch update broke today with the following error which was due to a missing soname entry in the older nss packages.
The error was identified and a post describing the error with a fix was posted to the ArchLinux news feed. Read Here
? sudo pacman -Syu
.....
.....
(201/201) checking for file conflicts [------------------------------------------------------------] 100%
error: failed to commit transaction (conflicting files)
nss: /usr/lib/p11-kit-trust.so exists in filesystem
lib32-nss: /usr/lib32/p11-kit-trust.so exists in filesystem
Errors occurred, no packages were upgraded.
? pacman -Syu --overwrite /usr/lib\*/p11-kit-trust.so
.....
.....
? sudo pacman -Syu
:: Synchronizing package databases...
core is up to date
extra is up to date
community is up to date
multilib is up to date
endeavouros is up to date 0.0 B 0.00 B/s 00:00 [c o o o o o o o o o o o o o o o o o o o ] 0%
:: Starting full system upgrade...
there is nothing to do