httpd was failing to enable suexec on start-up even when httpd-suexec was installed. I recompiled httpd-2.0.50-3 from source, without making any changes whatsoever to the SRPM, and installed my recompiled RPM, and it's now enabling suexec correctly. While I'm at it, I'd like to point out that your warning if SuexecUserGroup is specified and /usr/sbin/suexec is not found is not sufficient, because many people rely on suexec being used implicitly for CGI scripts in user directories, and you're check won't warn if that isn't working because suexec wasn't detected. This can introduce security problems because it will allow user CGI scripts to run as apache when they weren't before merely because the admin didn't know to install httpd-suexec.
w.r.t first comment: had you installed httpd-suexec *before* starting httpd? Otherwise suexec won't be enabled. I can't reproduce a problem with that. w.r.t second comment: yes, I'm concerned about that too. The only solution I can really see is to add back an "httpd requires httpd-suexec" change, which somewhat defeats the point of the change in the first place. People would then have to install a dummy, empty httpd-suexec package to prevent suexec from being used. It's not very pretty.
Yes, I restarted httpd. Several times. Didn't help. I can't imagine that this has anything to do with my kernel version, but perhaps it does. I'm using 2.4.27-pre2-pac1, not the Red Hat 2.6.x kernel (because my machine locks up whenever I try to use it). I'm also using a somewhat older glibc, 2.3.3-31, because newer ones have a bug (#125948) with my kernel.
Ah, if you had apr-0.9.4-19 or earlier with httpd-2.0.50-3 there was a constant mismatch which caused this; rebuilding would have fixed it. apr-0.9.4-20 and later with (vanilla) httpd-2.0.50-3 and later will be OK, but you'll get the issue again if you use the package you built locally against -19 with a newer APR, sorry about this. httpd-2.0.50-4 requires httpd-suexec again to prevent the security model changing on upgrades. Update to this and apr-0.9.4-20 at the same time and the problem should not recur. Thanks a lot for the report.