As documented in the man page, makewhatis can take a subsections argument (-s). Unfortunately, this is currently broken due to the way arguments are referenced. This is a patch Ive been using for a while. Basicly, it allows the script to parse: -s "1 2 3" as "1 2 3" being one argument to -s, rather than just pairing the '1' to -s and choking on 2 and 3 as separate args.
Created attachment 13815 [details, diff] trivial patch to makewhatis
Confirmed, looks like an obvious flaw in their logic. assigning to me...
This has been fixed in man-1.5m2, with the same fix you suggested :) 1.5m2 should be in portage shortly. RESOLVED, FIXED.