Add tools/run_big_endian_tests.sh

A tool to run tests on a big-endian system.
Uses an Alpine s390x Docker container.

.gitignore

@@ -459,3 +459,4 @@ uwp-project/Assets/fonts
 uwp-project/Assets/gendata
 uwp-project/Assets/ui_art
 !uwp-project/devilutionX_TemporaryKey.pfx
+/.s390x-ccache/

tools/Dockerfile.s390x

@@ -0,0 +1,13 @@
+FROM s390x/alpine
+
+# This command uses the `wget` from BusyBox.
+RUN wget -nv -nc https://github.com/diasurgical/devilutionx-assets/releases/download/v2/spawn.mpq -P /opt/
+
+# We use clang instead of GCC to have ASAN. GCC does not support ASAN with musl.
+# We also need to install GCC because it provides crtbeginS.o:
+# https://pkgs.alpinelinux.org/contents?file=crtbeginS.o&path=&name=gcc&branch=edge&repo=main&arch=s390x
+RUN apk add --no-cache \
+	clang15 gcc binutils musl-dev ninja cmake ccache sdl2-dev sdl2_image-dev fmt-dev \
+	libpng-dev bzip2-dev gtest-dev
+
+ENV CC=/usr/bin/clang CXX=/usr/bin/clang++

tools/run_big_endian_tests.sh

@@ -0,0 +1,21 @@
+#!/usr/bin/env bash
+
+cd -- "$(dirname -- "${BASH_SOURCE[0]}")/.."
+PARALLELISM="$(getconf _NPROCESSORS_ONLN)"
+
+set -xeuo pipefail
+
+if [[ "$(docker images -q devilutionx-s390x-test)" = "" ]]; then
+	docker run --rm --privileged multiarch/qemu-user-static --reset -p yes
+	docker build -f tools/Dockerfile.s390x -t devilutionx-s390x-test tools/
+fi
+
+# We disable ASAN and UBSAN for now because of:
+# https://gitlab.alpinelinux.org/alpine/aports/-/issues/14435
+docker run -u "$(id -u "$USER"):$(id -g "$USER")" --rm --mount "type=bind,source=${PWD},target=/host" devilutionx-s390x-test sh -c "cd /host && \
+export CCACHE_DIR=/host/.s390x-ccache && \
+cmake -S. -Bbuild-s390x-test -G Ninja -DASAN=OFF -DUBSAN=OFF -DCMAKE_BUILD_TYPE=Debug -DCMAKE_C_COMPILER=/usr/bin/clang -DCMAKE_CXX_COMPILER=/usr/bin/clang++ \
+  -DNONET=ON -DNOSOUND=ON -DVERSION_NUM=1.0.0 -DVERSION_SUFFIX=FFFFFFF && \
+ln -sf /opt/spawn.mpq /host/build-s390x-test/spawn.mpq && \
+cmake --build build-s390x-test -j ${PARALLELISM} && \
+ctest --test-dir build-s390x-test --output-on-failure -j ${PARALLELISM}"