…lots1

* origin/master: (63 commits)
  bpo-41627: Distinguish 32 and 64-bit user site packages on Windows (pythonGH-22098)
  bpo-38585: Remove references to defusedexpat (pythonGH-22095)
  bpo-41721: Add xlc options (pythonGH-22096)
  bpo-40486: Specify what happens if directory content change diring iteration (pythonGH-22025)
  bpo-41638: Improve ProgrammingError message for absent parameter. (pythonGH-21999)
  bpo-41713: _signal doesn't use multi-phase init (pythonGH-22087)
  bpo-41700: Skip test if the locale is not supported (pythonGH-22081)
  [doc] Update documentation on logging optimization. (pythonGH-22075)
  Fix 'gather' rules in the python parser generator (pythonGH-22021)
  bpo-41697: Correctly handle KeywordOrStarred when parsing arguments in the parser (pythonGH-22077)
  [doc] Fix a typo in the graphlib docs (python#22030)
  bpo-1635741: Port _signal module to multi-phase init (PEP 489) (pythonGH-22049)
  bpo-39883: Use BSD0 license for code in docs (pythonGH-17635)
  bpo-39010: Improve test shutdown (python#22066)
  bpo-41696: Fix handling of debug mode in asyncio.run (python#22069)
  bpo-41690: Use a loop to collect args in the parser instead of recursion (pythonGH-22053)
  closes bpo-41689: Preserve text signature from tp_doc in C heap type creation. (pythonGH-22058)
  Fix invalid escape sequences in the peg_highlight Sphinx extension (pythonGH-22047)
  bpo-41675: Modernize siginterrupt calls (pythonGH-22028)
  bpo-41685: Don't pin setuptools version anymore in Doc/Makefile (pythonGH-22062)
  ...

…ythonGH-22098)

Also fixes the error message returned when sysconfig fails to interpolate a variable correctly.