Description of problem:

Tcl's XML parser reports an error when an xml-stylesheet Processing Instruction is encountered in the parsed XML.

Version-Release number of selected component (if applicable):

RPM Package name tclxml Version = 3.1

How reproducible:

everytime

Steps to Reproduce:
1. Create Script:
#!/usr/bin/tclsh
package require xml

proc OnXmlElementStart {args} {}
proc OnXmlElementEnd {args} {}
proc OnXmlCharacterData {args} {}

set MyXml {<?xml version="1.0" encoding="UTF-8"?>
<?xml-stylesheet type="text/xsl" media="screen" href="http://feedproxy.google.com/~d/styles/rss2full.xsl"?>
<rss>
</rss>
}

set parser [::xml::parser -elementstartcommand OnXmlElementStart -elementendcommand  OnXmlElementEnd -characterdatacommand OnXmlCharacterData] 
if [catch {$parser parse $MyXml} perr] {
	puts "Parse failed: $perr\n"
}

$parser free

2. Run That.
  
Actual results:

Parse failed: illegalcharacters {characters "xml" not permitted in processing instruction target "xml-stylesheet"}

Expected results:

No error messages.

Additional info:

I was able to fix this on my system by rolling back a somewhat recent change
to sgmlparser.tcl:

diff original_sgmlparser.tcl fixed_sgmlparser.tcl 
609c609
< 			} elseif {[regexp {[xX][mM][lL]} $tag]} {
---
> 			} elseif {[regexp {^[xX][mM][lL]$} $tag]} {

I've submitted a comment to an up-stream bug report here:

http://sourceforge.net/tracker/index.php?func=detail&aid=1649537&group_id=13178&atid=113178