xpointer: Remove support for XPointer locations

The latest spec for what it essentially an XPath extension seems to be
this working draft from 2002:

    https://www.w3.org/TR/xptr-xpointer/

The xpointer() scheme is listed as "being reviewed" in the XPointer
registry since at least 2006. libxml2 seems to be the only modern
software that tries to implement this spec, but the code has many bugs
and quality issues.

If you configure --with-legacy, old symbols are retained for ABI
compatibility.

include/libxml/xpath.h

@@ -104,22 +104,15 @@ typedef enum {
     XPATH_BOOLEAN = 2,
     XPATH_NUMBER = 3,
     XPATH_STRING = 4,
-#ifdef LIBXML_XPTR_LOCS_ENABLED
-    XPATH_POINT = 5,
-    XPATH_RANGE = 6,
-    XPATH_LOCATIONSET = 7,
-#endif
     XPATH_USERS = 8,
     XPATH_XSLT_TREE = 9  /* An XSLT value tree, non modifiable */
 } xmlXPathObjectType;
 
-#ifndef LIBXML_XPTR_LOCS_ENABLED
 /** DOC_DISABLE */
 #define XPATH_POINT 5
 #define XPATH_RANGE 6
 #define XPATH_LOCATIONSET 7
 /** DOC_ENABLE */
-#endif
 
 typedef struct _xmlXPathObject xmlXPathObject;
 typedef xmlXPathObject *xmlXPathObjectPtr;