Although code to add __attribute__((destructor)) to libwbclient has been added to the 3.5.x series, the corresponding configure check is not.
The configure check has been added in master with 36e736871e28665ffcbbc4d0c87e1a2b60fcf0e0
Please add it as otherwise pam_winbind keeps leaking descriptors on dlcose()
I would read Simo's comment as an ACK of this patch. I'm the author, Simo likes it. Simo, you might want to assign it to email@example.com.
Pushed to v3-5-test.
Closing out bug report.