[3.11] gh-96005: Handle WASI ENOTCAPABLE in getpath (GH-96006) (GH-96034) (GH-96038)

- On WASI `ENOTCAPABLE` is now mapped to `PermissionError`.
- The `errno` modules exposes the new error number.
- `getpath.py` now ignores `PermissionError` when it cannot open landmark
  files `pybuilddir.txt` and `pyenv.cfg`.

Modules/getpath.py

@@ -351,11 +351,11 @@ if not home and not py_setpath:
         try:
             # Read pyvenv.cfg from one level above executable
             pyvenvcfg = readlines(joinpath(venv_prefix, VENV_LANDMARK))
-        except FileNotFoundError:
+        except (FileNotFoundError, PermissionError):
             # Try the same directory as executable
             pyvenvcfg = readlines(joinpath(venv_prefix2, VENV_LANDMARK))
             venv_prefix = venv_prefix2
-    except FileNotFoundError:
+    except (FileNotFoundError, PermissionError):
         venv_prefix = None
         pyvenvcfg = []
 
@@ -475,7 +475,7 @@ if ((not home_was_set and real_executable_dir and not py_setpath)
         # File exists but is empty
         platstdlib_dir = real_executable_dir
         build_prefix = joinpath(real_executable_dir, VPATH)
-    except FileNotFoundError:
+    except (FileNotFoundError, PermissionError):
         if isfile(joinpath(real_executable_dir, BUILD_LANDMARK)):
             build_prefix = joinpath(real_executable_dir, VPATH)
             if os_name == 'nt':