Disable extras in RHEL builds

The `buildrequire_extras` dependencies are unwanted in RHEL.

python-lxml.spec

@@ -1,6 +1,6 @@
 Name:           python-lxml
 Version:        4.9.2
-Release:        3%{?dist}
+Release:        4%{?dist}
 Summary:        XML processing library combining libxml2/libxslt with the ElementTree API
 
 # The lxml project is licensed under BSD-3-Clause
@@ -27,7 +27,8 @@ BuildRequires:  python3-devel
 # - [html5] Requires html5lib BuildRequires lxml
 # - [htmlsoup] Requires beautifulsoup4 Requires lxml
 # Hence we provide a bcond to disable this buildtime requirement.
-%bcond buildrequire_extras 1
+# These subpackages are disabled outright in RHEL builds.
+%bcond buildrequire_extras %{undefined rhel}
 
 %global _description \
 lxml is a Pythonic, mature binding for the libxml2 and libxslt libraries. It\
@@ -39,15 +40,19 @@ XML Schema, XSLT, C14N and much more.
 
 %package -n     python3-lxml
 Summary:        %{summary}
+%if %{undefined rhel}
 Suggests:       python3-lxml+cssselect
 Suggests:       python3-lxml+html5
 Suggests:       python3-lxml+htmlsoup
+%endif
 
 %description -n python3-lxml %{_description}
 
 Python 3 version.
 
+%if %{undefined rhel}
 %pyproject_extras_subpkg -n python3-lxml cssselect html5 htmlsoup
+%endif
 
 %prep
 %autosetup -n lxml-%{version} -p1
@@ -79,6 +84,9 @@ cp -a build/lib.%{python3_platform}-*/* src/
 %doc README.rst src/lxml/isoschematron/resources/xsl/iso-schematron-xslt1/readme.txt
 
 %changelog
+* Tue May 30 2023 Yaakov Selkowitz <yselkowi@redhat.com> - 4.9.2-4
+- Disable extra subpackages in RHEL builds
+
 * Mon May 29 2023 Tomáš Hrnčiar <thrnciar@redhat.com> - 4.9.2-3
 - Skip failing test to avoid FTBFS