Looks like the change came from the recent version bump for libxml2 which removed some functions regarding FTP, a rebuild for libxml2 with it enabled resolves the missing symbol, not the crash though.
EDIT exiv2 has been fixed, had to fix the cmake config files in order to get digikam to find it and start the build, build for digikam is running atm on buildmasters, once done you should be able to update it to the latest revision, probably doesn’t fix the crash, but should fix the missing symbol (that actually got removed in the 2.10.* versions from libxml2).