fix(PythonQtPythonInclude): Undefine C <ctype> macros after Python.h to avoid libstdc++ <locale> clashes

On older Apple toolchains (e.g., macOS 10.7.4/Xcode 4.3.3 with libstdc++ 4.2.1),
including <Python.h> pulls in <ctype.h>, which defines macros like isspace/isalnum.
When C++ headers such as <locale> (transitively included by moc-generated code)
declare the templated overloads (e.g., `bool std::isspace(_CharT, const std::locale&)`),
those C macros expand and break compilation with errors.

In `PythonQtPythonInclude.h`, explicitly `#undef` the problematic <ctype.h> macros
(isalnum, isalpha, islower, isspace, isupper, tolower, toupper) after including Python
headers. This keeps macro pollution out of downstream C++ includes and lets the std:: functions/
overloads compile cleanly.

It fixes error like the following:

```
  /usr/include/c++/4.2.1/bits/localefwd.h:57:21: error:
  too many arguments provided to function-like macro invocation
      isspace(_CharT, const locale&);
```

```
moc_PythonQtStdDecorators.cxx:152:25:
error: expected unqualified-id
        case 4: _t->emit((*reinterpret_cast<
QObject*(*)>(_a[1])),(*reinterpret_cast< const
`
```

(cherry picked from commit commontk/PythonQt@4ce028d)

Author: pieper

src/PythonQtPythonInclude.h

@@ -142,4 +142,27 @@
 #define PyBytes_FromStringAndSize PyString_FromStringAndSize
 #endif
 
+/*
+ * The following undefs for C standard library macros prevent
+ * build errors of the following type on macOS 10.7.4 and XCode 4.3.3
+ *
+/usr/include/c++/4.2.1/bits/localefwd.h:57:21: error: too many arguments provided to function-like macro invocation
+    isspace(_CharT, const locale&);
+                    ^
+/usr/include/c++/4.2.1/bits/localefwd.h:56:5: error: 'inline' can only appear on functions
+    inline bool
+    ^
+/usr/include/c++/4.2.1/bits/localefwd.h:57:5: error: variable 'isspace' declared as a template
+    isspace(_CharT, const locale&);
+    ^
+*/
+#undef isalnum
+#undef isalpha
+#undef islower
+#undef isspace
+#undef isupper
+#undef tolower
+#undef toupper
+
 #endif
+