Open About Krita and see Third-party libraries. The 4th entry from bottom is libiff, that I think should be libtiff. Also the link page is currently missing.
Git commit f338ae2d4ebde955a842ce9b49d633404a798435 by Boudewijn Rempt. Committed on 14/06/2018 at 14:55. Pushed by rempt into branch 'master'. Fix link to libtiff M +1 -1 krita/data/aboutdata/libraries.txt https://commits.kde.org/krita/f338ae2d4ebde955a842ce9b49d633404a798435
Git commit 438074f365f840f542cc3dd65d12248b997344a9 by Andrey Kamakin, on behalf of Boudewijn Rempt. Committed on 26/06/2018 at 14:18. Pushed by akamakin into branch 'akamakin/T8628-multithreading-optimization'. Fix link to libtiff M +1 -1 krita/data/aboutdata/libraries.txt https://commits.kde.org/krita/438074f365f840f542cc3dd65d12248b997344a9
It becomes to old URL again. I checked it version 4.1.7 on mac.
No, this commit was never merged to the 4.1 branch. It's still fixed in master.