gitlab-ci: arm64 cross compiling

First I tried to build in a full sysroot, but I didn't figure out why
ld never found the libraries (this was on fedora, which might have
been part of the problem - if you just need a toolchain for kernel
corss-building fedora is perfectly fine).

Then I tried using debian's multiarch stuff, which worked a lot
better, except there's some minor gotchas:
- some libraries conflict and can't be multi-arch installed
- some libraries are buggy and cause conflicts when installing
- pkgconfig and ld get confused with some other libraries and pick the
  first one they find (i.e. the x86_64 one, not the arm64 one).
That means we need a new docker image with just the cross libaries
installed as -dev packages, and none of the native ones.

Next up I tried to run the tests. Meson has really nice support for an
exe wrapper, and qemu happily runs arm64 on x86_64. With that I
managed to run some tests successfully (it's not even that slow!). But
most are run through a script, and the scrip...

.gitlab-ci.yml

@@ -57,6 +57,15 @@ build:tests-debian-meson:
     paths:
       - meson-test-list.txt
 
+build:tests-debian-meson-arm64:
+  image: $CI_REGISTRY/$CI_PROJECT_PATH/igt-debian-arm64:latest
+  stage: build
+  script:
+    - PKG_CONFIG_PATH=/usr/lib/aarch64-linux-gnu/pkgconfig/ meson --cross-file meson-cross-arm64.txt build
+    - ninja -C build
+  artifacts:
+    paths:
+      - build
 
 build:tests-debian-autotools:
   image: $CI_REGISTRY/$CI_PROJECT_PATH/igt-debian:latest
@@ -77,6 +86,14 @@ test:ninja-test:
   stage: test
   script: ninja -C build test
 
+test:ninja-test-arm64:
+  when: manual
+  image: $CI_REGISTRY/$CI_PROJECT_PATH/igt-debian-arm64:latest
+  dependencies:
+    - build:tests-debian-meson-arm64
+  stage: test
+  script: ninja -C build test
+
 test:test-list-diff:
   dependencies:
     - build:tests-debian-autotools
@@ -117,6 +134,22 @@ containers:igt-debian:
     - docker build -t $CI_REGISTRY/$CI_PROJECT_PATH/igt-debian -f Dockerfile.debian .
     - docker push $CI_REGISTRY/$CI_PROJECT_PATH/igt-debian
 
+containers:igt-debian-arm64:
+  stage: containers
+  image: docker:stable
+  only:
+    changes:
+      - Dockerfile.debian-arm64
+  services:
+    - docker:dind
+  variables:
+    DOCKER_HOST: tcp://docker:2375
+    DOCKER_DRIVER: overlay2
+  script:
+    - docker login -u gitlab-ci-token -p $CI_JOB_TOKEN $CI_REGISTRY
+    - docker build -t $CI_REGISTRY/$CI_PROJECT_PATH/igt-debian-arm64 -f Dockerfile.debian-arm64 .
+    - docker push $CI_REGISTRY/$CI_PROJECT_PATH/igt-debian-arm64
+
 containers:igt-fedora:
   stage: containers
   image: docker:stable

Dockerfile.debian-arm64

+FROM debian:stretch-backports
+
+RUN apt-get update
+RUN apt-get install -y \
+			flex \
+			bison \
+			pkg-config \
+			x11proto-dri2-dev \
+			python-docutils \
+			valgrind \
+			peg
+
+RUN dpkg --add-architecture arm64
+RUN apt-get update
+RUN apt-get install -y \
+			gcc-aarch64-linux-gnu \
+			libpciaccess-dev:arm64 \
+			libkmod-dev:arm64 \
+			libprocps-dev:arm64 \
+			libunwind-dev:arm64 \
+			libdw-dev:arm64 \
+			zlib1g-dev:arm64 \
+			liblzma-dev:arm64 \
+			libssl-dev:arm64 \
+			libcairo-dev:arm64 \
+			libpixman-1-dev:arm64 \
+			libudev-dev:arm64 \
+			libgsl-dev:arm64 \
+			libasound2-dev:arm64 \
+			libjson-c-dev:arm64 \
+			libcurl4-openssl-dev:arm64 \
+			libxrandr-dev:arm64 \
+			libxv-dev:arm64
+
+RUN apt-get install -t stretch-backports -y \
+					meson \
+					libdrm-dev:arm64 \
+					qemu-user
+
+# autotools build deps
+RUN apt-get install -y \
+			autoconf \
+			automake \
+			xutils-dev \
+			libtool \
+			make

meson-cross-arm64.txt

+[binaries]
+c = '/usr/bin/aarch64-linux-gnu-gcc'
+ar = '/usr/bin/aarch64-linux-gnu-gcc-ar'
+strip = '/usr/bin/aarch64-linux-gnu-strip'
+pkgconfig = 'pkg-config'
+exe_wrapper = 'qemu-aarch64'
+
+[host_machine]
+system = 'linux'
+cpu_family = 'aarch64'
+cpu = 'aarch64'
+endian = 'little'