Thanks, Ben. Confirmed fixed in libbsd/0.8.7-1.1.I installed libbsd0_0.8.7-1.1_amd64.deb on a buster VM and it no longer hangs after lightdm credentials are entered (the xfce4-session hang reported in #899080):
http://ftp.debian.org/debian/pool/main/libb/libbsd/libbsd0_0.8.7-1.1_amd64.deb
Kind regards, -- Ben Caradoc-Davies <b...@transient.nz> Director Transient Software Limited <https://transient.nz/> New Zealand