CI: Use FDO_CI_CONCURRENT

$FDO_CI_CONCURRENT is provided by in the CI environment by the fd.o
GitLab runners to tell us how many parallel processes would be 'good' to
use.

Use this to override the default Ninja invocation which uses as many
CPUs as available, and instead tell it to use as many parallel processes
as the runner thinks we should during the build process.

Tests are invoked using `meson test` inside a virtme/QEmu VM; whilst
Meson's test backend will use as many processors as availble, virtme
will by default create a single-CPU VM. So if we create a VM with as
many CPUs as we should have parallel processes, we can let it use all of
them. This also requires quadrupling the requested RAM so ASan doesn't
force us straight into OOM.

Suggested by @daenzer.

Signed-off-by: Daniel Stone <daniels@collabora.com>

.gitlab-ci.yml

@@ -44,7 +44,7 @@ container_prep:
   - git clone --depth=1 https://gitlab.freedesktop.org/wayland/wayland-protocols
   - export WAYLAND_PROTOCOLS_DIR="$(pwd)/prefix-wayland-protocols"
   - export PKG_CONFIG_PATH="$WAYLAND_PROTOCOLS_DIR/share/pkgconfig:$PKG_CONFIG_PATH"
-  - export MAKEFLAGS="-j4"
+  - export MAKEFLAGS="-j${FDO_CI_CONCURRENT:-4}"
   - cd wayland-protocols
   - git show -s HEAD
   - mkdir build
@@ -64,9 +64,9 @@ container_prep:
   - export PATH=~/.local/bin:$PATH
   - cd "$BUILDDIR"
   - meson --prefix="$PREFIX" -Db_sanitize=address ${MESON_OPTIONS} ..
-  - ninja -k0
+  - ninja -k0 -j${FDO_CI_CONCURRENT:-4}
   - ninja install
-  - virtme-run --rw --pwd --kimg /weston-virtme/bzImage --kopt quiet --script-dir ../.gitlab-ci/virtme-scripts --qemu-opts -m 1024
+  - virtme-run --rw --pwd --kimg /weston-virtme/bzImage --kopt quiet --script-dir ../.gitlab-ci/virtme-scripts --qemu-opts -m 4096 -smp ${FDO_CI_CONCURRENT:-4}
   - TEST_RES=$(cat $TESTS_RES_PATH)
   - rm $TESTS_RES_PATH
   - cp -R /weston-virtme ./
@@ -91,7 +91,7 @@ container_prep:
   - export PATH=~/.local/bin:$PATH
   - cd "$BUILDDIR"
   - meson --prefix="$PREFIX" ${MESON_OPTIONS} ..
-  - ninja -k0
+  - ninja -k0 -j${FDO_CI_CONCURRENT:-4}
   - ninja install
   - ninja clean
   artifacts: