fix error support clang

[sgzGary]

I meet problems like this when I use clang:
[ 75s] src/dmidecodemodule.c:916:28: error: incompatible function pointer types initializing 'PyCFunction' (aka 'struct _object ()(struct _object *, struct _object *)') with an expression of type 'PyObject *(PyObject *, PyObject *, PyObject *)' (aka 'struct _object *(struct _object *, struct _object *, struct _object *)') [-Wincompatible-function-pointer-types]
[ 75s] 916 | {(char *)"xmlapi", dmidecode_xmlapi, METH_VARARGS | METH_KEYWORDS,
[ 75s] | ^~~~~~~~~~~~~~~~
[ 75s] src/dmidecodemodule.c:997:9: warning: 'xmlXPathInit' is deprecated [-Wdeprecated-declarations]
[ 75s] 997 | xmlXPathInit();
[ 75s] | ^
[ 75s] /usr/include/libxml2/libxml/xpath.h:562:1: note: 'xmlXPathInit' has been explicitly marked deprecated here
[ 75s] 562 | XML_DEPRECATED
[ 75s] | ^
[ 75s] /usr/include/libxml2/libxml/xmlversion.h:447:43: note: expanded from macro 'XML_DEPRECATED'
[ 75s] 447 | # define XML_DEPRECATED attribute((deprecated))
[ 75s] | ^
[ 75s] src/dmidecodemodule.c:1027:72: error: incompatible function pointer types passing 'void (void )' to parameter of type 'PyCapsule_Destructor' (aka 'void ()(struct _object *)') [-Wincompatible-function-pointer-types]
[ 75s] 1027 | PyModule_AddObject(module, "options", PyCapsule_New(opt, NULL, destruct_options));
[ 75s] | ^~~~~~~~~~~~~~~~
[ 75s] /usr/include/python3.11/pycapsule.h:31:26: note: passing argument to parameter 'destructor' here
[ 75s] 31 | PyCapsule_Destructor destructor);
[ 75s] | ^
[ 75s] 5 warnings and 2 errors generated.
so i did some change