gitlab: split alpha testing into a legacy container

The current bookworm compiler doesn't build the static binaries due to
bug #1054412 and it might be awhile before it gets fixed. The problem
of keeping older architecture compilers running isn't going to go away
so lets prepare the ground. Create a legacy container and move some
tests around so the others can get upgraded.

Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Signed-off-by: Alex Bennée <alex.bennee@linaro.org>
Message-Id: <20231029145033.592566-4-alex.bennee@linaro.org>

tests/docker/dockerfiles/debian-legacy-test-cross.docker

@@ -0,0 +1,46 @@
+# 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
+#
+# 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
+
+# Duplicate deb line as deb-src
+RUN cat /etc/apt/sources.list | sed "s/^deb\ /deb-src /" >> /etc/apt/sources.list
+
+RUN export DEBIAN_FRONTEND=noninteractive && \
+    apt-get update && \
+    apt-get install -y eatmydata && \
+    eatmydata apt-get dist-upgrade -y && \
+    apt build-dep -yy qemu
+
+# Add extra build tools and as many cross compilers as we can for testing
+RUN DEBIAN_FRONTEND=noninteractive eatmydata \
+        apt install -y --no-install-recommends \
+        bison \
+        ccache \
+        clang  \
+        flex \
+        git \
+        ninja-build \
+        gcc-alpha-linux-gnu \
+        libc6.1-dev-alpha-cross \
+        python3-pip \
+        python3-setuptools \
+        python3-venv \
+        python3-wheel
+
+RUN /usr/bin/pip3 install tomli
+
+ENV QEMU_CONFIGURE_OPTS --disable-system --disable-docs --disable-tools
+ENV DEF_TARGET_LIST alpha-linux-user
+# As a final step configure the user (if env is defined)
+ARG USER
+ARG UID
+RUN if [ "${USER}" ]; then \
+  id ${USER} 2>/dev/null || useradd -u ${UID} -U ${USER}; fi