[...]

  git checkout -b <new-branch-name>
HEAD is now at 187b4c0 - updated to 0.29
fatal: HEAD does not point to a branch
Available branches: master
Searching for tag auto/ti/libwacom-0.29-1...
Searching for tag auto/ti/libwacom-0_29-1...
--2018-08-31 23:29:32--  http://distfiles.pld-linux.org/distfiles/by-md5/3/a/3a6b614b57518b25a102dcd9e51d6681/libwacom-0.29.tar.bz2
Resolving distfiles.pld-linux.org (distfiles.pld-linux.org)... 193.239.45.41
Connecting to distfiles.pld-linux.org (distfiles.pld-linux.org)|193.239.45.41|:80... connected.
HTTP request sent, awaiting response... 200 OK
Length: 495549 (484K) [application/x-bzip2]
Saving to: 'libwacom-0.29.tar.bz2'
     0K .......... .......... .......... .......... .......... 10% 1.21M 0s
    50K .......... .......... .......... .......... .......... 20% 2.42M 0s
   100K .......... .......... .......... .......... .......... 30% 80.9M 0s
   150K .......... .......... .......... .......... .......... 41%  341M 0s
   200K .......... .......... .......... .......... .......... 51% 2.50M 0s
   250K .......... .......... .......... .......... .......... 61% 72.8M 0s
   300K .......... .......... .......... .......... .......... 72% 41.3M 0s
   350K .......... .......... .......... .......... .......... 82%  391M 0s
   400K .......... .......... .......... .......... .......... 92% 2.62M 0s
   450K .......... .......... .......... ...                  100%  399M=0.1s
2018-08-31 23:29:32 (4.66 MB/s) - 'libwacom-0.29.tar.bz2' saved [495549/495549]
Building target platforms: i686-linux
Wrote: /home/users/builder/rpm/SRPMS/libwacom-0.29-1.src.rpm
exit status 0
Tagging with prefix: auto/ti/
HEAD is now at 187b4c0 - updated to 0.29
fatal: HEAD does not point to a branch
Writing git revision for tag auto/ti/libwacom-0.29-1
On detached HEAD. Use -r BRANCHNAME to override
error: Macro %_builddir has empty 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.1616
+ umask 022
+ cd /home/users/builder/rpm/BUILD
+ rm -rf libwacom-0.29
Begin-TLD-Builder-Info
Build-Time: user:0.59s sys:0.08s real:1.84s (faults io:0 non-io:93710)
Files queued for ftp:
    500636 libwacom-0.29-1.src.rpm
       185 libwacom-0.29-1.src.rpm.uploadinfo
End-TLD-Builder-Info