This is a plugin for AWN (Avant Window Navigator) which, according to the logs, you didn't have installed so far. It has been tried to be installed as dependency of awn-applet-mutliload-ng-gtk2. What failed during this process was the building of one of AWN's dependencies, libdesktop-agnostic, not awn-applet-mutliload-ng-gtk2.
According to the pinned comment in https://aur.archlinux.org/packages/libdesktop-agnostic/ the issue is known and a workaround is to install libdesktop-agnostic-git instead. However, I am wondering if you really want to install awn-applet-mutliload-ng-gtk2 in the first place since you don't use AWN at all. There are further packages of multiload-ng for other environments (Xfce panel, Mate panel, LXDE panel, systray etc...). Most probably a different package will better suit your needs.
Pinned Comments
PhotonX commented on 2017-12-30 16:15
Manual intervention required in the -3 update: Either install using "--force" or remove the currently installed version and then install the updated one.
PhotonX commented on 2017-12-30 16:15
Manual intervention required in the -3 update: Either install using "--force" or remove the currently installed version and then install the updated one.