contrib: add support for rhel9

Makefile

@@ -203,9 +203,11 b' i18n/hg.pot: $(PYFILES) $(DOCFILES) i18n'
 packaging_targets := \
   rhel7 \
   rhel8 \
+  rhel9 \
   deb \
   docker-rhel7 \
   docker-rhel8 \
+  docker-rhel9 \
   docker-debian-bullseye \
   docker-debian-buster \
   docker-debian-stretch \

contrib/packaging/Makefile

@@ -15,7 +15,8 b' FEDORA_RELEASE := 31'
 
 RHEL_RELEASES := \
   7 \
-  8
+  8 \
+  9
 
 # Build a Python for these RHEL (and derivatives) releases.
 RHEL_WITH_PYTHON_RELEASES :=

contrib/packaging/docker/rhel9

@@ -1,8 +1,12 b''
-FROM rockylinux/rockylinux:8
+FROM rockylinux/rockylinux:9
 
 RUN groupadd -g %GID% build && \
     useradd -u %UID% -g %GID% -s /bin/bash -d /build -m build
 
+RUN dnf install 'dnf-command(config-manager)' -y
+# crb repository is necessary for docutils
+RUN dnf config-manager --set-enabled crb
+
 RUN yum install -y \
 	gcc \
 	gettext \