code: def _get_default_compiler():
      if re.match("cygwin.*", sys.platform) is not None:
          return "unix"
      if os.name == "nt":
          return "msvc"
      if (
          sys.platform == "darwin"
          and "clang" in platform.python_compiler()
      ):
          return "clang"
      return "unix"
  
imports: import contextlib
  import logging
  import os
  import os.path
  import platform
  import re
  import sys
  from c_common.fsutil import match_glob
  from c_common.tables import parse_table
  from ..source import resolve, good_file
  from .None import errors
  from .None import pure, gcc
  from .errors import PreprocessorError, PreprocessorFailure, ErrorDirectiveError, MissingDependenciesError, OSMismatchError
  from .common import FileInfo, SourceLine
label_desc: Use image node_id 10 for calling a global function with example usage: _get_default_compiler() and returns: str, str, str, str