make check fails glsl/glcpp/tests/glcpp-test-cr-lf.sh test.

$ ./glsl/glcpp/tests/glcpp_test.py ./glsl/glcpp/glcpp glsl/glcpp/tests --windows --oldmac
[...]
  File "./glsl/glcpp/tests/glcpp_test.py", line 221, in <module>
    main()
  File "./glsl/glcpp/tests/glcpp_test.py", line 211, in main
    success = success and test_oldmac(args)
  File "./glsl/glcpp/tests/glcpp_test.py", line 169, in test_oldmac
    return _replace_test(args, '\r')
  File "./glsl/glcpp/tests/glcpp_test.py", line 144, in _replace_test
    args.glcpp, tmpfile, testfile + '.expected', nl_format=replace)
  File "./glsl/glcpp/tests/glcpp_test.py", line 65, in test_output
    stdin=subprocess.PIPE)
  File "/System/Library/Frameworks/Python.framework/Versions/2.7/lib/python2.7/subprocess.py", line 710, in __init__
    errread, errwrite)
  File "/System/Library/Frameworks/Python.framework/Versions/2.7/lib/python2.7/subprocess.py", line 1223, in _execute_child
    errpipe_read, errpipe_write = self.pipe_cloexec()
  File "/System/Library/Frameworks/Python.framework/Versions/2.7/lib/python2.7/subprocess.py", line 1175, in pipe_cloexec
    r, w = os.pipe()
OSError: [Errno 24] Too many open files