gh-108765: Python.h no longer includes <ctype.h> (#108831)

Remove <ctype.h> in C files which don't use it; only sre.c and
_decimal.c still use it.

Remove _PY_PORT_CTYPE_UTF8_ISSUE code from pyport.h:

* Code added by commit b5047fd019
  in 2004 for MacOSX and FreeBSD.
* Test removed by commit 52ddaefb6b
  in 2007, since Python str type now uses locale independent
  functions like Py_ISALPHA() and Py_TOLOWER() and the Unicode
  database.

Modules/_sre/sre.c replaces _PY_PORT_CTYPE_UTF8_ISSUE with new
functions: sre_isalnum(), sre_tolower(), sre_toupper().

Remove unused includes:

* _localemodule.c: remove <stdio.h>.
* getargs.c: remove <float.h>.
* dynload_win.c: remove <direct.h>, it no longer calls _getcwd()
  since commit fb1f68ed7c (in 2001).

Objects/abstract.c

@@ -9,9 +9,8 @@
 #include "pycore_pyerrors.h"      // _PyErr_Occurred()
 #include "pycore_pystate.h"       // _PyThreadState_GET()
 #include "pycore_unionobject.h"   // _PyUnion_Check()
-#include <ctype.h>
-#include <stddef.h>               // offsetof()
 
+#include <stddef.h>               // offsetof()
 
 
 /* Shorthands to return certain errors */

Objects/floatobject.c

@@ -16,8 +16,7 @@
 #include "pycore_pystate.h"       // _PyInterpreterState_GET()
 #include "pycore_structseq.h"     // _PyStructSequence_FiniBuiltin()
 
-#include <ctype.h>
-#include <float.h>
+#include <float.h>                // DBL_MAX
 #include <stdlib.h>               // strtol()
 
 /*[clinic input]

Objects/longobject.c

@@ -10,10 +10,8 @@
 #include "pycore_runtime.h"       // _PY_NSMALLPOSINTS
 #include "pycore_structseq.h"     // _PyStructSequence_FiniBuiltin()
 
-#include <ctype.h>
-#include <float.h>
-#include <stddef.h>
-#include <stdlib.h>               // abs()
+#include <float.h>                // DBL_MANT_DIG
+#include <stddef.h>               // offsetof
 
 #include "clinic/longobject.c.h"
 /*[clinic input]

Objects/typeobject.c

@@ -19,8 +19,6 @@
 #include "pycore_weakref.h"       // _PyWeakref_GET_REF()
 #include "opcode.h"               // MAKE_CELL
 
-
-#include <ctype.h>
 #include <stddef.h>               // ptrdiff_t
 
 /*[clinic input]