[...]

fatal: HEAD does not point to a branch
No conditional flags passed
from available:
--with   :	
--without:	 tests
Available branches: AC-branch master
--2016-03-24 11:38:18--  http://distfiles.pld-linux.org/distfiles/by-md5/3/b/3b08b110c89c3ff2eef127f00093c19e/Math-BigInt-GMP-1.48.tar.gz
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: 59490 (58K) [application/x-gzip]
Saving to: 'Math-BigInt-GMP-1.48.tar.gz'
     0K .......... .......... .......... .......... .......... 86%  896K 0s
    50K ........                                              100% 16.5M=0.06s
2016-03-24 11:38:18 (1.01 MB/s) - 'Math-BigInt-GMP-1.48.tar.gz' saved [59490/59490]
Building target platforms: i686-linux
Wrote: /home/users/builder/rpm/SRPMS/perl-Math-BigInt-GMP-1.48-1.src.rpm
exit status 0
Tagging with prefix: auto/ti/
HEAD is now at e76ff31... - up to 1.48
fatal: HEAD does not point to a branch
No conditional flags passed
from available:
--with   :	
--without:	 tests
Writing git revision for tag auto/ti/perl-Math-BigInt-GMP-1.48-1
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.72133
+ umask 022
+ cd /home/users/builder/rpm/BUILD
+ rm -rf Math-BigInt-GMP-1.48
Begin-PLD-Builder-Info
Build-Time: user:2.58s sys:1.23s real:4.51s (faults io:0 non-io:184003)
Files queued for ftp:
     65750 perl-Math-BigInt-GMP-1.48-1.src.rpm
       197 perl-Math-BigInt-GMP-1.48-1.src.rpm.uploadinfo
End-PLD-Builder-Info