This test appears to work properly on Debian 13/Trixie. It is possible
we no longer need a specific "legacy" cross test and this can be fixed
on a deeper level, so consider this patch more of an RFC and a request
for help performing this upgrade.

Signed-off-by: John Snow <jsnow@redhat.com>
---
 .../dockerfiles/debian-legacy-test-cross.docker  | 16 +++++-----------
 1 file changed, 5 insertions(+), 11 deletions(-)

diff --git a/tests/docker/dockerfiles/debian-legacy-test-cross.docker b/tests/docker/dockerfiles/debian-legacy-test-cross.docker
index 5a6616b7d39..293f31a07d6 100644
--- a/tests/docker/dockerfiles/debian-legacy-test-cross.docker
+++ b/tests/docker/dockerfiles/debian-legacy-test-cross.docker
@@ -1,18 +1,13 @@
 # Docker legacy cross-compiler target (tests and minimal qemu)
 #
-# Compilers for some of our older targets which we cant currently
-# upgrade. Currently:
-#
-#   libc6.1-dev-alpha-cross: https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=1054412
-#   sh4-linux-user: binaries don't run with bookworm compiler
-#
 # As we are targeting check-tcg here we only need minimal qemu
 # dependencies and the relevant cross compilers.
 
-FROM docker.io/library/debian:11-slim
+FROM docker.io/library/debian:13-slim
 
-# Duplicate deb line as deb-src
-RUN cat /etc/apt/sources.list | sed "s/^deb\ /deb-src /" >> /etc/apt/sources.list
+# Add deb-src repository sources
+RUN sed -i "s/^Types: deb$/Types: deb deb-src/" \
+    /etc/apt/sources.list.d/debian.sources
 
 RUN export DEBIAN_FRONTEND=noninteractive && \
     apt-get update && \
@@ -35,12 +30,11 @@ RUN DEBIAN_FRONTEND=noninteractive eatmydata \
         libc6-dev-sh4-cross \
         python3-pip \
         python3-setuptools \
+        python3-tomli \
         python3-venv \
         python3-wheel && \
         dpkg-query --showformat '${Package}_${Version}_${Architecture}\n' --show > /packages.txt
 
-RUN /usr/bin/pip3 install tomli
-
 ENV QEMU_CONFIGURE_OPTS --disable-system --disable-docs --disable-tools
 ENV DEF_TARGET_LIST alpha-linux-user,sh4-linux-user
 ENV MAKE /usr/bin/make
-- 
2.53.0