[...]

y body
error: Macro %_builddir has empty body
Executing(--clean): env -i TMP=/home/users/builder/tmp HOME=/home/users/builder PATH=/bin:/usr/bin:/usr/sbin:/sbin:/usr/X11R6/bin TMPDIR=/home/users/builder/tmp  /bin/sh -e /home/users/builder/tmp/rpm-tmp.19018
+ umask 022
+ cd /home/users/builder/rpm/BUILD
+ rm -rf lxml-4.2.3
Begin-TLD-Builder-Info
Build-Time: user:0.77s sys:0.10s real:63.60s (faults io:0 non-io:108211)
Files queued for ftp:
   4415027 python-lxml-4.2.3-1.src.rpm
       189 python-lxml-4.2.3-1.src.rpm.uploadinfo
End-TLD-Builder-Info