Postgres 9.3.1 and Self Test Failure "pg_regress: no *.source files found"

The following dropped out of `make check` for Postgres 9.3.1.

Any ideas how to clear the error? I could not locate answers when
searching the phrase.

Thanks in advance.

**********

$ make check
...

mkdir ./testtablespace
../../../src/test/regress/pg_regress --inputdir=.
--temp-install=./tmp_check --top-builddir=../../..   --dlpath=.
--schedule=./parallel_schedule
pg_regress: no *.source files found in
"/home/jwalton/postgresql-9.3.1/src/test/regress/input"
make[1]: *** [check] Error 2
make[1]: Leaving directory `/home/jwalton/postgresql-9.3.1/src/test/regress'
make: *** [check] Error 2
$