BUG #5963: make -j4 check fails

The following bug has been logged online:

Bug reference: 5963
Logged by: Gavin Flower
Email address: gavin(dot)flower(at)archidevsys(dot)co(dot)nz
PostgreSQL version: 9.1alpha5
Operating system: x86_64 Linux
Description: make -j4 check fails
Details:

After executing
time -j4 make
I went to initiate the testing (note: I deleted the directory, re-extracted
and repeated the compile for each of the following options):

executing
time make check
works (All 126 tests passed)

but executing
time make -j4 check
fails (I don't see any obvious problem in the log file):
[...]
============== creating temporary installation ==============

pg_regress: installation failed
Examine
/home/gavin/AAA/updates/postgresql/postgresql-9.1alpha5/src/test/regress/log
/install.log for the reason.
Command was: "make" -C "../../.."
DESTDIR="/home/gavin/AAA/updates/postgresql/postgresql-9.1alpha5/src/test/re
gress/./tmp_check/install" install >
"/home/gavin/AAA/updates/postgresql/postgresql-9.1alpha5/src/test/regress/lo
g/install.log" 2>&1
make[2]: *** [check] Error 2
make[2]: Leaving directory
`/home/gavin/AAA/updates/postgresql/postgresql-9.1alpha5/src/test/regress'
make[1]: *** [check] Error 2
make[1]: Leaving directory
`/home/gavin/AAA/updates/postgresql/postgresql-9.1alpha5/src/test'
make: *** [check] Error 2

real 0m3.253s
user 0m1.666s
sys 0m1.141s