gh-106320: Remove private AC converter functions (#108505)

Move these private functions to the internal C API
(pycore_abstract.h):

* _Py_convert_optional_to_ssize_t()
* _PyNumber_Index()

Argument Clinic now emits #include "pycore_abstract.h" when these
functions are used.

The parser of the c-analyzer tool now uses a list of files which use
the limited C API, rather than a list of files using the internal C
API.

Tools/c-analyzer/c_parser/preprocessor/gcc.py

@@ -3,26 +3,14 @@ import re
 
 from . import common as _common
 
-# Modules/socketmodule.h uses pycore_time.h which needs the Py_BUILD_CORE
-# macro. Usually it's defined by the C file which includes it.
-# Other header files have a similar issue.
-NEED_BUILD_CORE = {
-    # Header ".h" files
-    'cjkcodecs.h',
-    'multibytecodec.h',
-    'socketmodule.h',
-
-    # Argument Clinic ".c.h" header files
-    '_testclinic.c.h',
-    '_testclinic_depr.c.h',
-    '_winapi.c.h',
-    'fcntlmodule.c.h',
-    'overlapped.c.h',
-    'posixmodule.c.h',
-    'selectmodule.c.h',
-    'sha3module.c.h',
-    'termios.c.h',
-}
+# The following C files must not be built with Py_BUILD_CORE,
+# because they use the limited C API.
+USE_LIMITED_C_API = frozenset((
+    '_testcapimodule.c',
+    '_testclinic_limited.c',
+    'xxlimited.c',
+    'xxlimited_35.c',
+))
 
 TOOL = 'gcc'
 
@@ -81,8 +69,9 @@ def preprocess(filename,
         cwd = os.path.abspath(cwd or '.')
     filename = _normpath(filename, cwd)
 
+    print(filename)
     postargs = POST_ARGS
-    if os.path.basename(filename) in NEED_BUILD_CORE:
+    if os.path.basename(filename) not in USE_LIMITED_C_API:
         postargs += ('-DPy_BUILD_CORE=1',)
 
     text = _common.preprocess(