When I try to update @system after --sync-ing, I get a conflict on
/readline/.

/Bash/ wants /readline/ 8.0 but the profile specifies /readline/ 7.0 and
lots of other packages are linked against 7.0.  Just rebuilding those
packages probably won't help, because they don't know about /readline/ 8.0.

Would the right thing, the easiest thing, be to define my own profile
17.1.1 or something, where I specify /readline/ 8.0 in the profile?