MCAST_JOIN_SOURCE_GROUPin Vista. The workaround is quite simple:
1. open the generated apr.h;
APR_HAVE_IPV6to 1 (or there would be a link error with the function
Btw, just got back to Beijing this morning. Well, there's rather a lot of work to do.
Update1: ASF Bugzilla Bug 40398
Update2: APR 1.2.9 on Vista