doc build error on Fedora 38

Hi,

I'm getting the following errors while building PDF docs on Fedora 38
(and works fine on Fedora 37). This is how I build them:

./configure
cd doc/src/sgml/
make postgres-A4.pdf

and getting the following errors. Google did not help me that much. This
is libxml2-2.10.3 and libxslt 1.1.37 (same on Fedora 37).

========================================================================
{ \
echo "<!ENTITY version \"16devel\">"; \
echo "<!ENTITY majorversion \"16\">"; \
} > version.sgml
'/usr/bin/perl' ./mk_feature_tables.pl YES
../../../src/backend/catalog/sql_feature_packages.txt
../../../src/backend/catalog/sql_features.txt > features-supported.sgml
'/usr/bin/perl' ./mk_feature_tables.pl NO
../../../src/backend/catalog/sql_feature_packages.txt
../../../src/backend/catalog/sql_features.txt > features-
unsupported.sgml
'/usr/bin/perl' ./generate-errcodes-table.pl
../../../src/backend/utils/errcodes.txt > errcodes-table.sgml
'/usr/bin/perl' ./generate-keywords-table.pl . > keywords-table.sgml
/usr/bin/xmllint --nonet --path . --path . --output postgres-full.xml --
noent --valid postgres.sgml
I/O error : Attempt to load network entity
http://www.oasis-open.org/docbook/xml/4.5/docbookx.dtd
postgres.sgml:21: warning: failed to load external entity
"http://www.oasis-open.org/docbook/xml/4.5/docbookx.dtd"
]>
^
postgres.sgml:23: element book: validity error : No declaration for
attribute id of element book
<book id="postgres">
^
postgres.sgml:24: element title: validity error : No declaration for
element title
<title>PostgreSQL &version; Documentation</title>
^
postgres.sgml:27: element corpauthor: validity error : No declaration
for element corpauthor
<corpauthor>The PostgreSQL Global Development Group</corpauthor>
^
postgres.sgml:28: element productname: validity error : No declaration
for element productname
<productname>PostgreSQL</productname>
^
postgres.sgml:29: element productnumber: validity error : No declaration
for element productnumber
<productnumber>&version;</productnumber>
^
postgres.sgml:3: element date: validity error : No declaration for
element date
legal.sgml:6: parser error : Entity 'ndash' not defined
<year>1996&ndash;2023</year>
^
legal.sgml:14: parser error : Entity 'copy' not defined
<productname>PostgreSQL</productname> is Copyright &copy;
1996&ndash;2023
^
legal.sgml:14: parser error : Entity 'ndash' not defined
<productname>PostgreSQL</productname> is Copyright &copy;
1996&ndash;2023
^
legal.sgml:19: parser error : Entity 'copy' not defined
<productname>Postgres95</productname> is Copyright &copy; 1994&ndash;5
^
legal.sgml:19: parser error : Entity 'ndash' not defined
<productname>Postgres95</productname> is Copyright &copy; 1994&ndash;5
^
legal.sgml:49: parser error : chunk is not well balanced

^
postgres.sgml:30: parser error : Entity 'legal' failed to parse
&legal;
^
make: *** [Makefile:73: postgres-full.xml] Error 1

========================================================================

Any ideas?

Regards,
--
Devrim Gündüz
Open Source Solution Architect, PostgreSQL Major Contributor
Twitter: @DevrimGunduz , @DevrimGunduzTR