I got openwebmail 2.53+ working with speedy AND the c-wrappers:
1 - download the speedy 2.22 sources from
http://daemoninc.com/SpeedyCGI/download.html
2 - extract the tar.gz and edit this for compiling:
/src/speedy_backend_main.h:
-#define speedy_new(s,n,t) New(123,s,n,t)
+#define speedy_new(s,n,t) Newx(s,n,t)
(http://sourceforge.net/p/speedycgi/bugs/91/#7fc6)
3 - perl Makefile.PL; make; make install (don't bother adding the -DIAMSUID)
4 - change the #! line on your openwebmail*.pl to
/usr/bin/speedy -- -T/tmp/speedy
5 - on your openwebmail*.pl directory, run the c wrapper script (change the dir accordingly):
perl misc/tools/wrapsuid/wrapsuid.pl /var/www/owtest/cgi-bin/openwebmail
6 - chmod u+s openwebmail*pl
That worked on my squeeze server (I'm preparing to upgrade to wheezy, so I'll need that working).
(please note that my openwebmail 2.53 is not the stock 2.53, but probably something between that and 3beta, but it should work for both)