[...]

do so (now or later) by using -b with the checkout command again. Example:
  git checkout -b new_branch_name
HEAD is now at bac8ba9... - updated to 0.9.7 - removed obsolete mibstore,xserver-1.19 patches
fatal: HEAD does not point to a branch
Available branches: master
Searching for tag auto/ti/xorg-driver-video-sisusb-0.9.7-1...
Searching for tag auto/ti/xorg-driver-video-sisusb-0_9_7-1...
--2017-04-13 07:27:09--  http://distfiles.pld-linux.org/distfiles/by-md5/6/f/6ffdc63f4636bccf729c3903c0fe2df3/xf86-video-sisusb-0.9.7.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: 411894 (402K) [application/x-bzip2]
Saving to: 'xf86-video-sisusb-0.9.7.tar.bz2'
     0K .......... .......... .......... .......... .......... 12% 1.05M 0s
    50K .......... .......... .......... .......... .......... 24% 2.06M 0s
   100K .......... .......... .......... .......... .......... 37%  193M 0s
   150K .......... .......... .......... .......... .......... 49%  346M 0s
   200K .......... .......... .......... .......... .......... 62% 2.08M 0s
   250K .......... .......... .......... .......... .......... 74%  311M 0s
   300K .......... .......... .......... .......... .......... 87%  126M 0s
   350K .......... .......... .......... .......... .......... 99%  397M 0s
   400K ..                                                    100% 4273G=0.09s
2017-04-13 07:27:10 (4.15 MB/s) - 'xf86-video-sisusb-0.9.7.tar.bz2' saved [411894/411894]
Building target platforms: i686-linux
Wrote: /home/users/builder/rpm/SRPMS/xorg-driver-video-sisusb-0.9.7-1.src.rpm
exit status 0
Tagging with prefix: auto/ti/
HEAD is now at bac8ba9... - updated to 0.9.7 - removed obsolete mibstore,xserver-1.19 patches
fatal: HEAD does not point to a branch
Writing git revision for tag auto/ti/xorg-driver-video-sisusb-0.9.7-1
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.87205
+ umask 022
+ cd /home/users/builder/rpm/BUILD
+ rm -rf xf86-video-sisusb-0.9.7
Begin-TLD-Builder-Info
Build-Time: user:0.56s sys:0.16s real:1.78s (faults io:0 non-io:91438)
Files queued for ftp:
    417998 xorg-driver-video-sisusb-0.9.7-1.src.rpm
       202 xorg-driver-video-sisusb-0.9.7-1.src.rpm.uploadinfo
End-TLD-Builder-Info