Description:
------------
If the body of the bugs contains a character that's invalid in XML, it's not properly escaped in the feed, resulting in malformed XML.

Test script:
---------------
For instance, bug #52774 contains the character \05 in its body. This character is not then properly escaped in a feed.

Example: http://bugs.php.net/rss/search.php?search_for=Proxy+object%27s+store+free+callback+calls+zval_ptor_dtor+on+already+freed+data&boolean=0&limit=30&order_by=&direction=DESC&cmd=display&status=All&bug_type=All&package_name%5B0%5D=%2AGeneral+Issues&package_name%5B1%5D=Feature%2FChange+Request&package_name%5B2%5D=Documentation+problem&package_name%5B3%5D=Translation+problem&package_name%5B4%5D=Doc+Build+problem&package_name%5B5%5D=Website+problem&package_name%5B6%5D=Online+Doc+Editor+problem&package_name%5B7%5D=Systems+problem&package_name%5B8%5D=Output+Control&package_name%5B9%5D=Performance+problem&package_name%5B10%5D=Reproducible+crash&package_name%5B11%5D=Scripting+Engine+problem&package_name%5B12%5D=SPL+related&package_name%5B13%5D=Reflection+related&package_name%5B14%5D=Session+related&package_name%5B15%5D=Filter+related&package_name%5B16%5D=Streams+related&package_name%5B17%5D=PHP-GTK+related&package_name%5B18%5D=PDO+related&package_name%5B19%5D=PHAR+related&package_name%5B20%5D=%2ACompile+Issues&package_name%5B21%5D=Compile+Failure&package_name%5B22%5D=Compile+Warning&package_name%5B23%5D=%2AConfiguration+Issues&package_name%5B24%5D=Dynamic+loading&package_name%5B25%5D=PHP+options%2Finfo+functions&package_name%5B26%5D=Safe+Mode%2Fopen_basedir&package_name%5B27%5D=Windows+Installer&package_name%5B28%5D=%2AWeb+Server+problem&package_name%5B29%5D=CGI+related&package_name%5B30%5D=Apache+related&package_name%5B31%5D=Apache2+related&package_name%5B32%5D=IIS+related&package_name%5B33%5D=iPlanet+related&package_name%5B34%5D=PWS+related&package_name%5B35%5D=Servlet+related&package_name%5B36%5D=Other+web+server&package_name%5B37%5D=FPM+related&package_name%5B38%5D=%2ACalendar+problems&package_name%5B39%5D=Date%2Ftime+related&package_name%5B40%5D=Calendar+related&package_name%5B41%5D=%2ACompression+related&package_name%5B42%5D=Bzip2+Related&package_name%5B43%5D=Zip+Related&package_name%5B44%5D=ZZiplib+Related&package_name%5B45%5D=Zlib+Related&package_name%5B46%5D=%2ADirectory%2FFilesystem+functions&package_name%5B47%5D=Directory+function+related&package_name%5B48%5D=Filesystem+function+related&package_name%5B49%5D=%2ADirectory+Services+problems&package_name%5B50%5D=LDAP+related&package_name%5B51%5D=%2ADatabase+Functions&package_name%5B52%5D=Adabas-D+related&package_name%5B53%5D=dBase+related&package_name%5B54%5D=DBM%2FDBA+related&package_name%5B55%5D=DBX+related&package_name%5B56%5D=FrontBase+related&package_name%5B57%5D=Informix+related&package_name%5B58%5D=Ingres+II+related&package_name%5B59%5D=InterBase+related&package_name%5B60%5D=mSQL+related&package_name%5B61%5D=MSSQL+related&package_name%5B62%5D=MySQL+related&package_name%5B63%5D=MySQLi+related&package_name%5B64%5D=OCI8+related&package_name%5B65%5D=Oracle+related&package_name%5B66%5D=ODBC+related&package_name%5B67%5D=PostgreSQL+related&package_name%5B68%5D=Solid+related&package_name%5B69%5D=SQLite+related&package_name%5B70%5D=Sybase+%28dblib%29+related&package_name%5B71%5D=Sybase-ct+%28ctlib%29+related&package_name%5B72%5D=%2AData+Exchange+functions&package_name%5B73%5D=JSON+related&package_name%5B74%5D=WDDX+related&package_name%5B75%5D=%2AExtensibility+Functions&package_name%5B76%5D=COM+related&package_name%5B77%5D=Java+related&package_name%5B78%5D=ncurses+related&package_name%5B79%5D=Program+Execution&package_name%5B80%5D=POSIX+related&package_name%5B81%5D=PCNTL+related&package_name%5B82%5D=Readline+related&package_name%5B83%5D=Semaphore+related&package_name%5B84%5D=Win32API+related&package_name%5B85%5D=%2AE-commerce+functions&package_name%5B86%5D=Verisign+Payflow+Pro+related&package_name%5B87%5D=%2AGraphics+related&package_name%5B88%5D=EXIF+related&package_name%5B89%5D=GD+related&package_name%5B90%5D=GetImageSize+related&package_name%5B91%5D=Ming+related&package_name%5B92%5D=%2ALanguages%2FTranslation&package_name%5B93%5D=Gettext+related&package_name%5B94%5D=ICONV+related&package_name%5B95%5D=mbstring+related&package_name%5B96%5D=Recode+related&package_name%5B97%5D=%2AMail+Related&package_name%5B98%5D=IMAP+related&package_name%5B99%5D=Mail+related&package_name%5B100%5D=%2AMath+Functions&package_name%5B101%5D=BC+math+related&package_name%5B102%5D=GNU+MP+related&package_name%5B103%5D=Math+related&package_name%5B104%5D=%2AEncryption+and+hash+functions&package_name%5B105%5D=mcrypt+related&package_name%5B106%5D=hash+related&package_name%5B107%5D=mhash+related&package_name%5B108%5D=OpenSSL+related&package_name%5B109%5D=%2ANetwork+Functions&package_name%5B110%5D=Network+related&package_name%5B111%5D=SNMP+related&package_name%5B112%5D=FTP+related&package_name%5B113%5D=HTTP+related&package_name%5B114%5D=Sockets+related&package_name%5B115%5D=%2APDF+functions&package_name%5B116%5D=ClibPDF+related&package_name%5B117%5D=FDF+related&package_name%5B118%5D=PDF+related&package_name%5B119%5D=%2AProgramming+Data+Structures&package_name%5B120%5D=Class%2FObject+related&package_name%5B121%5D=Arrays+related&package_name%5B122%5D=Strings+related&package_name%5B123%5D=Variables+related&package_name%5B124%5D=%2ARegular+Expressions&package_name%5B125%5D=PCRE+related&package_name%5B126%5D=Regexps+related&package_name%5B127%5D=%2ASpelling+functions&package_name%5B128%5D=Pspell+related&package_name%5B129%5D=%2ASearch+functions&package_name%5B130%5D=mnoGoSearch+related&package_name%5B131%5D=%2AXML+functions&package_name%5B132%5D=DOM+XML+related&package_name%5B133%5D=SOAP+related&package_name%5B134%5D=SimpleXML+related&package_name%5B135%5D=XML+Reader&package_name%5B136%5D=XML+Writer&package_name%5B137%5D=XML+related&package_name%5B138%5D=XMLRPC-EPI+related&package_name%5B139%5D=XSLT+related&package_name%5B140%5D=%2AURL+Functions&package_name%5B141%5D=cURL+related&package_name%5B142%5D=URL+related&package_name%5B143%5D=%2AUnicode+Issues&package_name%5B144%5D=Unicode+Function+Upgrades+related&package_name%5B145%5D=I18N+and+L10N+related&package_name%5B146%5D=Unicode+Engine+related&package_name%5B147%5D=Unknown%2FOther+Function&package_name%5B148%5D=%2AFunction+Specific&package_name%5B149%5D=%2AInstall+and+Config&package_name%5B150%5D=%2ASession+related&package_name%5B151%5D=%2AZlib+related&package_name%5B152%5D=Calendar+problems&package_name%5B153%5D=CCVS+related&package_name%5B154%5D=Compile+Problem&package_name%5B155%5D=Cybercash+related&package_name%5B156%5D=Dynamic+loading+related&package_name%5B157%5D=FrontPage+related&package_name%5B158%5D=Installation+problem&package_name%5B159%5D=Livedocs+problem&package_name%5B160%5D=Misbehaving+function&package_name%5B161%5D=NIS+related&package_name%5B162%5D=Other&package_name%5B163%5D=Parser+error&package_name%5B164%5D=PEAR+related&package_name%5B165%5D=PECL+related&package_name%5B166%5D=Sablotron+XSL&package_name%5B167%5D=Sybase+related&package_name%5B168%5D=Unicode+Function+Upgrades+relate&package_name%5B169%5D=unknown&php_os=&phpver=&assign=&author_email=&bug_age=0&bug_updated=0

Expected result:
----------------
The character should have been escaped.

Actual result:
--------------
XML parsing failed

XML parsing failed: syntax error (Line: 266, Character: 62)

Reparse document as HTML
Error: invalid character

Specification: http://www.w3.org/TR/REC-xml/#NT-Char

263: object
264: 0x028102c0 {object=0x0280db38 property=0x028101d0 }
265:     object: 0x0280db38 {value={...} refcount__gc=2 type='\05' ...}
266:     property: 0x028101d0 {value={...} refcount__gc=1515870810 type='Z' ...}
267: 
268: 
269: