Drop unsupported libxml2 2.10.0 symbols

The Docbook parser module has been removed completely.  Support for
XPointer locations (ranges and points) is disabled by default, and will
eventually be removed completely.  Given that the maintainer comments
on the latter: "Be warned that this part of the code base is buggy and
had many security issues in the past", it seems to be prudent to no
longer build with XPointer locations support right away.

To be able to build against libxml2 2.10.0, we remove the export
definitions for Windows.

Closes GH-9358.

Author: cmb69

UPGRADING.INTERNALS

@@ -62,6 +62,8 @@ PHP 8.2 INTERNALS UPGRADE NOTES
 2. Build system changes
 ========================
 
+* Unsupported libxml2 2.10.0 symbols are no longer exported on Windows.
+
 ========================
 3. Module changes
 ========================

ext/libxml/php_libxml2.def

@@ -1,5 +1,4 @@
 EXPORTS
-__docbDefaultSAXHandler
 __htmlDefaultSAXHandler
 __oldXMLWDcompatibility
 __xmlBufferAllocScheme
@@ -53,17 +52,6 @@ cdataBlock
 characters
 checkNamespace
 comment
-docbCreateFileParserCtxt
-docbCreatePushParserCtxt
-docbDefaultSAXHandlerInit
-docbEncodeEntities
-docbFreeParserCtxt
-docbParseChunk
-docbParseDoc
-docbParseDocument
-docbParseFile
-docbSAXParseDoc
-docbSAXParseFile
 elementDecl
 endDocument
 endElement
@@ -137,7 +125,6 @@ htmlSetMetaEncoding
 htmlTagLookup
 ignorableWhitespace
 initGenericErrorDefaultFunc
-initdocbDefaultSAXHandler
 inithtmlDefaultSAXHandler
 initxmlDefaultSAXHandler
 inputPop
@@ -801,7 +788,6 @@ xmlRegisterHTTPPostCallbacks
 xmlRegisterInputCallbacks
 xmlRegisterNodeDefault
 xmlRegisterOutputCallbacks
-xmlRelaxNGCleanupTypes
 xmlRelaxNGDump
 xmlRelaxNGDumpTree
 xmlRelaxNGFree
@@ -849,7 +835,6 @@ xmlSAX2HasExternalSubset
 xmlSAX2HasInternalSubset
 xmlSAX2IgnorableWhitespace
 xmlSAX2InitDefaultSAXHandler
-xmlSAX2InitDocbDefaultSAXHandler
 xmlSAX2InitHtmlDefaultSAXHandler
 xmlSAX2InternalSubset
 xmlSAX2IsStandalone
@@ -1523,27 +1508,8 @@ xmlXPathWrapExternal
 xmlXPathWrapNodeSet
 xmlXPathWrapString
 xmlXPatherror
-xmlXPtrBuildNodeList
 xmlXPtrEval
-xmlXPtrEvalRangePredicate
-xmlXPtrFreeLocationSet
-xmlXPtrLocationSetAdd
-xmlXPtrLocationSetCreate
-xmlXPtrLocationSetDel
-xmlXPtrLocationSetMerge
-xmlXPtrLocationSetRemove
-xmlXPtrNewCollapsedRange
 xmlXPtrNewContext
-xmlXPtrNewLocationSetNodeSet
-xmlXPtrNewLocationSetNodes
-xmlXPtrNewRange
-xmlXPtrNewRangeNodeObject
-xmlXPtrNewRangeNodePoint
-xmlXPtrNewRangeNodes
-xmlXPtrNewRangePointNode
-xmlXPtrNewRangePoints
-xmlXPtrRangeToFunction
-xmlXPtrWrapLocationSet
 xmlBufContent
 xmlBufUse
 xmlBufferDetach