CI: add Ubuntu 24.10 and actually test 24.04 :-)

.cirrus.yml

@@ -149,10 +149,17 @@ opensuse_tumbleweed_task:
   << : *CI_TEMPLATE
   << : *SKIP_TASK_ON_PR
 
+ubuntu24_10_task:
+  container:
+    # Ubuntu 24.10 EOL: 2025-07-30
+    dockerfile: ci/ubuntu-24.10/Dockerfile
+    << : *RESOURCES_TEMPLATE
+  << : *CI_TEMPLATE
+
 ubuntu24_task:
   container:
     # Ubuntu 24.04 EOL: Jun 2029
-    dockerfile: ci/ubuntu-22.04/Dockerfile
+    dockerfile: ci/ubuntu-24.04/Dockerfile
     << : *RESOURCES_TEMPLATE
   << : *CI_TEMPLATE
 

ci/ubuntu-24.10/Dockerfile

@@ -0,0 +1,18 @@
+FROM ubuntu:24.10
+
+ENV DEBIAN_FRONTEND="noninteractive" TZ="America/Los_Angeles"
+
+# A version field to invalidate Cirrus's build cache when needed, as suggested in
+# https://github.com/cirruslabs/cirrus-ci-docs/issues/544#issuecomment-566066822
+ENV DOCKERFILE_VERSION 20241204
+
+RUN apt-get update && apt-get -y install \
+    bison \
+    cmake \
+    flex \
+    g++ \
+    gcc \
+    git \
+    make \
+  && apt autoclean \
+  && rm -rf /var/lib/apt/lists/*