I’ve packaged up libalpm.so.12 from pacman 5.2.2 and put it in the AUR: https://aur.archlinux.org/packages/libalpm12/
You can install this package and pamac-all (etc.) will work until a new/fixed version of Pamac is released.
Pamac itself won’t rebuild (yet) because meson will pick up libalpm 13 if it’s installed…
Pinging @FredBezies for info.
Hopefully that’ll help keep the forum clean of hundreds of threads asking the same thing 
I wouldn’t hold my breath. If it involves manually editing the PKGBUILD file for Pamac, most of Pamac users will be hopelessly clueless. I imagine most of them do not know how to edit a text file…
Users can install the package. If Fred updates the PKGBUILD then it will be installed automatically. 
Oh, I failed to notice that Fred is the maintainer of the AUR package for Pamac and thought that you were instructing Pamac users to manually build the package from the AUR with a different dependence.
Good god, take it easy there, Stephen King, I do want to be able to sleep tonight! 
I guess this is quite a prejudiced point of view. Some users might even be offended (not including myself). Not everybody using GUI is incapable of manually editing stuff. 
I think there even should be kind of a forum rule against making of elitist, condescending and derogatory comments about other users on the level of their knowledge or whatever tools they choose to use, GUI based or otherwise.
really!!!
No one was being condescending, no one made derogatory remarks, we were just having a laugh mate.
That said, have you seen the number of new topics on the same one subject, and their general quality? Clearly, a lot of people don’t bother doing a search anymore, you really think those would have the curiosity (or the confidence) needed to jump in and read, next step being edit, configuration files? It’s nowt to do with knowledge or the tool they use mate, it’s to do with how these particular users present themselves.
And again, no one was slagging them off for it, just expressing the expectation they won’t bother with text files.
Well, I beg to differ.
This seems to be going well off topic, and the point Kresimir was making was that my original post implied that people had to edit the PKGBUILD of Pamac and rebuild it to make it work. What I had written was inaccurate (as I aimed the post at Fred) and so I have updated the OP to make it clearer.
I think it’s reasonable to say that it’s likely most people using Pamac - or Arch in general - are not familiar with editing PKGBUILD files on a regular basis for it to be second-nature to them.
That is, just because I am happy using aurutils and running my own binary repos doesn’t mean I can expect everyone else to.
More importantly - has anyone tried the libalpm12 package, and does it work for them?
I just installed and tested the package in an Arcolinux install which has pamac-all 10.1.2-1 and it worked 
This 
Unfortunately this issue exists on all forums and is nothing to do with Elitism. Most people just want to an instant answer without reading/searching about their issue first