Description:
------------
When the domxml_open_file function is called on a file that contains invalid entity (like &asdf;), PHP segfaults. Replacing the invalid entity with a valid one (like &) does not cause a segfault.

I'm using the DOMXML extension included with the PHP source (./configure --with-dom)

Reproduce code:
---------------
test.xml:
<?xml version="1.0" ?>
<roottag>
	<test testvalue="tom, dick &asdf; harry" />
</roottag>


test.php:
<?php
$dom = domxml_open_file("test.xml");
?>

Expected result:
----------------
Run the test.php file; PHP should return without an error:

# php test.php
#

Actual result:
--------------
# php test.php
Segmentation fault
#

According to gdb:
# gdb php
(gdb) run test.php
Starting program: /usr/local/bin/php test.php

Program received signal SIGSEGV, Segmentation fault.
0x08208fe5 in add_next_index_zval (arg=0x3, value=0x840526c) at /root/installs/php-4.3.10/Zend/zend_API.c:851
851             return zend_hash_next_index_insert(Z_ARRVAL_P(arg), &value, sizeof(zval *), NULL);
(gdb) bt
#0  0x08208fe5 in add_next_index_zval (arg=0x3, value=0x840526c) at /root/installs/php-4.3.10/Zend/zend_API.c:851
#1  0x080906c4 in domxml_error_ext (ctx=0x83f6fd0, msg=0x405f6fdb "%s") at /root/installs/php-4.3.10/ext/domxml/php_domxml.c:1460
#2  0x40546d9d in __xmlRaiseError (schannel=0, channel=0x809047c <domxml_error_ext>, data=0x83f6fd0, ctx=0x83f6fd0, nod=0x0, 
    domain=1, code=26, level=XML_ERR_FATAL, file=0x83ee6a8 "test.xml", line=3, str1=0x8404c92 "asdf", str2=0x0, str3=0x0, int1=0, 
    int2=0, msg=0x405e9bee "Entity '%s' not defined\n") at error.c:610
#3  0x4054a3fb in xmlFatalErrMsgStr (ctxt=0x83f6fd0, error=XML_ERR_UNDECLARED_ENTITY, msg=0x405e9bee "Entity '%s' not defined\n", 
    val=0x8404c92 "asdf") at parser.c:523
#4  0x40553b4e in xmlParseEntityRef__internal_alias (ctxt=0x83f6fd0) at parser.c:5873
#5  0x4054de47 in xmlParseAttValueComplex (ctxt=0x83f6fd0, attlen=0xbfffbe60, normalize=0) at parser.c:2859
#6  0x405557ac in xmlParseAttribute2 (ctxt=0x83f6fd0, pref=0x0, elem=0x8404c83 "test", prefix=0xbfffbe58, value=0xbfffbe5c, 
    len=0xbfffbe60, alloc=0xbfffbe64) at parser.c:7259
#7  0x40555ac5 in xmlParseStartTag2 (ctxt=0x83f6fd0, pref=0xbfffbea4, URI=0xbfffbea8, tlen=0xbfffbeac) at parser.c:7388
#8  0x40556e51 in xmlParseElement__internal_alias (ctxt=0x83f6fd0) at parser.c:7981
#9  0x40556cf2 in xmlParseContent__internal_alias (ctxt=0x83f6fd0) at parser.c:7905
#10 0x40557091 in xmlParseElement__internal_alias (ctxt=0x83f6fd0) at parser.c:8065
#11 0x405582cb in xmlParseDocument__internal_alias (ctxt=0x83f6fd0) at parser.c:8666
#12 0x080996f9 in domxml_document_parser (mode=0, loadtype=1, source=0x83f2524 "test.xml", data=0x0)
    at /root/installs/php-4.3.10/ext/domxml/php_domxml.c:4003
#13 0x08099a73 in zif_xmldocfile (ht=1, return_value=0x83ee644, this_ptr=0x0, return_value_used=1)
    at /root/installs/php-4.3.10/ext/domxml/php_domxml.c:4073
#14 0x0821b2ab in execute (op_array=0x83f2cbc) at /root/installs/php-4.3.10/Zend/zend_execute.c:1642
#15 0x08206b20 in zend_execute_scripts (type=8, retval=0x0, file_count=3) at /root/installs/php-4.3.10/Zend/zend.c:900
#16 0x081cc682 in php_execute_script (primary_file=0xbfffe560) at /root/installs/php-4.3.10/main/main.c:1736
#17 0x08221c5a in main (argc=2, argv=0xbfffe604) at /root/installs/php-4.3.10/sapi/cli/php_cli.c:822
#18 0x406425d9 in __libc_start_main () from /lib/libc.so.6