py-tensorflow, py-tensorflow1: fail to configure in trace mode

[chrstphrchvz (Christopher Chavez)]

Similar errors for both ports, which configure successfully without trace mode:

Executing:  cd "/opt/local/var/macports/build/_opt_local_var_macports_sources_github.com_macports_macports-ports_python_py-tensorflow1/py38-tensorflow1/work/tensorflow-1.15.3" && ./configure
FATAL: blaze_util::MakeCanonical('') failed: (error: 2): No such file or directory
Traceback (most recent call last):
  File "./configure.py", line 1602, in <module>
    main()
  File "./configure.py", line 1398, in main
    current_bazel_version = check_bazel_version(_TF_MIN_BAZEL_VERSION,
  File "./configure.py", line 477, in check_bazel_version
    curr_version = run_shell(
  File "./configure.py", line 156, in run_shell
    output = subprocess.check_output(cmd)
  File "/opt/local/Library/Frameworks/Python.framework/Versions/3.8/lib/python3.8/subprocess.py", line 411, in check_output
    return run(*popenargs, stdout=PIPE, timeout=timeout, check=True,
  File "/opt/local/Library/Frameworks/Python.framework/Versions/3.8/lib/python3.8/subprocess.py", line 512, in run
    raise CalledProcessError(retcode, process.args,
subprocess.CalledProcessError: Command '['bazel', '--batch', '--bazelrc=/dev/null', 'version']' returned non-zero exit status 36.
Command failed:  cd "/opt/local/var/macports/build/_opt_local_var_macports_sources_github.com_macports_macports-ports_python_py-tensorflow1/py38-tensorflow1/work/tensorflow-1.15.3" && ./configure
Exit code: 1
Warning: The following existing file was hidden from the build system by trace mode:
  /var
Error: Failed to configure py38-tensorflow1: configure failure: command execution failed

Executing:  cd "/opt/local/var/macports/build/_opt_local_var_macports_sources_github.com_macports_macports-ports_python_py-tensorflow/py38-tensorflow/work/tensorflow-2.2.0" && ./configure
FATAL: blaze_util::MakeCanonical('') failed: (error: 2): No such file or directory
Traceback (most recent call last):
  File "./configure.py", line 1551, in <module>
    main()
  File "./configure.py", line 1367, in main
    current_bazel_version = check_bazel_version(_TF_MIN_BAZEL_VERSION,
  File "./configure.py", line 482, in check_bazel_version
    curr_version = run_shell(
  File "./configure.py", line 159, in run_shell
    output = subprocess.check_output(cmd, stderr=stderr)
  File "/opt/local/Library/Frameworks/Python.framework/Versions/3.8/lib/python3.8/subprocess.py", line 411, in check_output
    return run(*popenargs, stdout=PIPE, timeout=timeout, check=True,
  File "/opt/local/Library/Frameworks/Python.framework/Versions/3.8/lib/python3.8/subprocess.py", line 512, in run
    raise CalledProcessError(retcode, process.args,
subprocess.CalledProcessError: Command '['bazel', '--batch', '--bazelrc=/dev/null', 'version']' returned non-zero exit status 36.
Command failed:  cd "/opt/local/var/macports/build/_opt_local_var_macports_sources_github.com_macports_macports-ports_python_py-tensorflow/py38-tensorflow/work/tensorflow-2.2.0" && ./configure
Exit code: 1
Warning: The following existing file was hidden from the build system by trace mode:
  /private/var/select/sh
Error: Failed to configure py38-tensorflow: configure failure: command execution failed

(I personally do not need these ports.)