[xslt] Weird whitespace after XSL transformation

[Manuzhai <mail manuzhai nl>]

Hello there,

I have a weird problem on one of my sites where I use XSLT (through PHP 
5's libxslt bindings) to do the templating part. The site where I have 
the problems is my personal weblog, and it has a single XSLT-stylesheet 
which creates XHTML from an Atom-like internal XML format.

The actual problem is that on one of my pages, I get very nicely 
formatted output XHTML (with lined out tabs etc.), while on the other I 
just get a jumble of (largely identical) XML output. This poses 
problems, however, since whitespace is significant in XHTML. This is 
also why it shows up in my design (the problem is with the tags I use; 
on the one page they're nicely formatted with a space in between, on the 
other one they're merged together without any whitespace).

These are the pages I'm talking about:

XHTML: http://manuzhai.nl/weblog/
XML: http://manuzhai.nl/weblog/?transform=false

XHTML: http://manuzhai.nl/weblog/comments/revival/
XML: http://manuzhai.nl/weblog/comments/revival/?transform=false

In the XML source, look at the <category> elements; these seem to be 
formatted similarly in both source pages. In the XHTML source, you can 
look for <a href="/weblog/tag/*/">.

I hope this is the right place for such a question, that someone can 
tell me why this happens and that I can fix it from within PHP.

Thanks in advance,

Manuzhai