Description of problem:
Package perl-XML-LibXML fails to build from source with libxml2-2.12.0 in Fedora Rawhide.

Entity: line 1: parser error : Char 0x0 out of allowed range
pseudoroot
          ^
Entity: line 1: parser error : PCDATA invalid Char value 0
pseudoroot
          ^
Entity: line 1: parser error : Char 0x0 out of allowed range
pseudoroot
          ^
<...>
          ^
Entity: line 1: parser error : PCDATA invalid Char value 0
pseudoroot
          ^
:8: parser error : Entity 'b' failed to parse
  <b>&b;</b>
        ^
t/44extent.t ....................................... 
Dubious, test returned 2 (wstat 512, 0x200)
Failed 7/7 subtests 
# Looks like your test exited with 2 before it could output anything.

Version-Release number of selected component (if applicable):
2.0209-2.fc39

Steps to Reproduce:
koji build --scratch f40 perl-XML-LibXML-2.0209-2.fc39.src.rpm

Additional info:
This package is tracked by Koschei. See:
https://koschei.fedoraproject.org/package/perl-XML-LibXML

Reproducible: Always