Suppress unreferenced '_unused_op' warning

On Windows, with cl /W4, we get following warning with Python 3.12:

  C:\Program Files\Python312\include\cpython/unicodeobject.h(203,57): warning C4100: '_unused_op': unreferenced formal parameter

Py_UNUSED hasn't changed in 5 years [1], but in Python 3.12 it started
being used in unicodeobject.h [2] so it became part of the public
interface. Because Py_UNUSED only prepended _unused_ to the parameter
name for MSVC [1], we get the C4100 warning when compiling with /W4.
In Python 3.13 this got fixed by adding a specific implementation of
Py_UNUSED for MSVC [3], so the warning is unique to Python 3.12.
However, as we don't know PY_VERSION_HEX _before_ including Python.h,
we'll indiscriminately suppress the C4100 while including Python.h.

[1] https://github.com/python/cpython/blame/3.12/Include/pymacro.h#L114-L123
[2] python/cpython@b2694ab
[3] python/cpython#107249

lass/python/python_common.h

@@ -23,7 +23,7 @@
  *	The Original Developer is the Initial Developer.
  *	
  *	All portions of the code written by the Initial Developer are:
- *	Copyright (C) 2004-2011 the Initial Developer.
+ *	Copyright (C) 2004-2024 the Initial Developer.
  *	All Rights Reserved.
  *	
  *	Contributor(s):
@@ -114,6 +114,13 @@
 #	undef _XOPEN_SOURCE
 #endif
 
+// Python 3.12 yields following warning in unicodeobject.h:
+// warning C4100: '_unused_op': unreferenced formal parameter
+#if LASS_COMPILER_TYPE == LASS_COMPILER_TYPE_MSVC
+#	pragma warning(push)
+#	pragma warning(disable: 4100) // unreferenced formal parameter
+#endif
+
 // Python >= 3.2 defines `PyType_Spec` in `object.h` which has a member called
 // `slots`. When combining this with Qt, `slots` may already be defined as a
 // macro. It is sufficient to temporarily undefine `slots` since this member
@@ -132,6 +139,10 @@
 
 #pragma pop_macro("slots")
 
+#if LASS_COMPILER_TYPE == LASS_COMPILER_TYPE_MSVC
+#	pragma warning(pop)
+#endif
+
 // oh r'ly? Because of some issue lost to ancient history, pyport.h will
 // redefine following functions on FreeBSD > 500039 (and Apple?),
 // causing really havoc with the C++ code.