bpo-35081: And pycore_lifecycle.h and pycore_pathconfig.h (GH-10273)

* And pycore_lifecycle.h and pycore_pathconfig.h headers to
  Include/internal/
* Move Py_BUILD_CORE specific code from coreconfig.h and
  pylifecycle.h to pycore_pathconfig.h and pycore_lifecycle.h
* Move _Py_wstrlist_XXX() definitions and _PyPathConfig code
  from pycore_state.h to pycore_pathconfig.h
* Move "Init" and "Fini" function definitions from pylifecycle.c to
  pycore_lifecycle.h.

Include/internal/pycore_pathconfig.h

@@ -0,0 +1,68 @@
+#ifndef Py_INTERNAL_PATHCONFIG_H
+#define Py_INTERNAL_PATHCONFIG_H
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+PyAPI_FUNC(void) _Py_wstrlist_clear(
+    int len,
+    wchar_t **list);
+PyAPI_FUNC(wchar_t**) _Py_wstrlist_copy(
+    int len,
+    wchar_t **list);
+PyAPI_FUNC(_PyInitError) _Py_wstrlist_append(
+    int *len,
+    wchar_t ***list,
+    const wchar_t *str);
+PyAPI_FUNC(PyObject*) _Py_wstrlist_as_pylist(
+    int len,
+    wchar_t **list);
+
+typedef struct _PyPathConfig {
+    /* Full path to the Python program */
+    wchar_t *program_full_path;
+    wchar_t *prefix;
+#ifdef MS_WINDOWS
+    wchar_t *dll_path;
+#else
+    wchar_t *exec_prefix;
+#endif
+    /* Set by Py_SetPath(), or computed by _PyPathConfig_Init() */
+    wchar_t *module_search_path;
+    /* Python program name */
+    wchar_t *program_name;
+    /* Set by Py_SetPythonHome() or PYTHONHOME environment variable */
+    wchar_t *home;
+    /* isolated and site_import are used to set Py_IsolatedFlag and
+       Py_NoSiteFlag flags on Windows in read_pth_file(). These fields
+       are ignored when their value are equal to -1 (unset). */
+    int isolated;
+    int site_import;
+} _PyPathConfig;
+
+#define _PyPathConfig_INIT \
+    {.module_search_path = NULL, \
+     .isolated = -1, \
+     .site_import = -1}
+/* Note: _PyPathConfig_INIT sets other fields to 0/NULL */
+
+PyAPI_DATA(_PyPathConfig) _Py_path_config;
+
+PyAPI_FUNC(void) _PyPathConfig_ClearGlobal(void);
+PyAPI_FUNC(_PyInitError) _PyPathConfig_SetGlobal(
+    const struct _PyPathConfig *config);
+
+PyAPI_FUNC(_PyInitError) _PyPathConfig_Calculate_impl(
+    _PyPathConfig *config,
+    const _PyCoreConfig *core_config);
+PyAPI_FUNC(PyObject*) _PyPathConfig_ComputeArgv0(int argc, wchar_t **argv);
+PyAPI_FUNC(int) _Py_FindEnvConfigValue(
+    FILE *env_file,
+    const wchar_t *key,
+    wchar_t *value,
+    size_t value_size);
+
+#ifdef __cplusplus
+}
+#endif
+#endif /* !Py_INTERNAL_PATHCONFIG_H */