GeezerVison

…9958)

Fix the test when run on an installed Python: use "abs_srcdir" of
sysconfig, and skip the test if the Python source code cannot be
found.

* Tools/patchcheck/patchcheck.py, Tools/freeze/test/freeze.py and
  Lib/test/libregrtest/utils.py now first try to get "abs_srcdir"
  from sysconfig, before getting "srcdir" from sysconfig.
* test.pythoninfo logs sysconfig "abs_srcdir".

(cherry picked from commit b89ed9d)

…ython#109970)

Not only check if src_dir exists, but look also for Lib/os.py
landmark.

(cherry picked from commit cc54bcf)

…src_ignore (pythonGH-110108)

(cherry picked from commit 20bc5f7)

…() (python#110149)

Call also copy_python_src_ignore() on listdir() names.

shutil.copytree(): replace set() with an empty tuple. An empty tuple
becomes a constant in the compiler and checking if an item is in an
empty tuple is cheap.

(cherry picked from commit 0def8c7)