Fix GH-14834: Error installing PHP when --with-pear is used

libxml2 2.13 makes changes to how the parsing state is set, update our
code accordingly. In particular, it started reporting entities within
attributes, while it should only report entities inside text nodes.

Closes GH-14837.

Author: nielsdos

ext/xml/compat.c

@@ -383,7 +383,7 @@ _get_entity(void *user, const xmlChar *name)
 		if (ret == NULL)
 			ret = xmlGetDocEntity(parser->parser->myDoc, name);
 
-		if (ret == NULL || (parser->parser->instate != XML_PARSER_ENTITY_VALUE && parser->parser->instate != XML_PARSER_ATTRIBUTE_VALUE)) {
+		if (ret == NULL || parser->parser->instate == XML_PARSER_CONTENT) {
 			if (ret == NULL || ret->etype == XML_INTERNAL_GENERAL_ENTITY || ret->etype == XML_INTERNAL_PARAMETER_ENTITY || ret->etype == XML_INTERNAL_PREDEFINED_ENTITY) {
 				/* Predefined entities will expand unless no cdata handler is present */
 				if (parser->h_default && ! (ret && ret->etype == XML_INTERNAL_PREDEFINED_ENTITY && parser->h_cdata)) {

ext/xml/tests/gh14834.phpt

@@ -0,0 +1,29 @@
+--TEST--
+GH-14834 (Error installing PHP when --with-pear is used)
+--EXTENSIONS--
+xml
+--FILE--
+<?php
+$xml = <<<XML
+<?xml version="1.0" encoding="UTF-8"?>
+<!DOCTYPE root [
+    <!ENTITY foo "ent">
+]>
+<root>
+  <element hint="hello&apos;world">&foo;<![CDATA[ &amp; ]]><?x &amp; ?></element>
+</root>
+XML;
+
+$parser = xml_parser_create();
+xml_set_character_data_handler($parser, function($_, $data) {
+    var_dump($data);
+});
+xml_parse($parser, $xml, true);
+?>
+--EXPECT--
+string(3) "
+  "
+string(3) "ent"
+string(7) " &amp; "
+string(1) "
+"