ci: Test ninja dist in meson jobs

While this isn't critical yet, it might become so at some point, so
let's make sure it keeps working.

Don't set the PIGLIT/XTEST_DIR variables for ninja dist, testing XTS
once against each DDX is enough (as part of ninja test).

Requires git in the docker image.

v2:
* Drop /usr/local/bin/xkbcomp symlink, no longer needed with xkbcomp
  1.4.1 (Peter Hutterer)

.gitlab-ci.yml

@@ -11,7 +11,7 @@ variables:
     UPSTREAM_REPO: xorg/xserver
     FDO_DISTRIBUTION_VERSION: buster-slim
     FDO_DISTRIBUTION_EXEC: 'env FDO_CI_CONCURRENT=${FDO_CI_CONCURRENT} bash .gitlab-ci/debian-install.sh'
-    FDO_DISTRIBUTION_TAG: "2021-01-19-xkbcomp"
+    FDO_DISTRIBUTION_TAG: "2021-01-19-git"
 
 include:
   - project: 'freedesktop/ci-templates'
@@ -72,13 +72,10 @@ autotools:
 
 meson:
     extends: .common-build-and-test
-    variables:
-        PIGLIT_DIR: /root/piglit
-        XTEST_DIR: /root/xts
     script:
         - meson -Dc_args="-fno-common" -Dprefix=/usr -Dxephyr=true -Dwerror=true $MESON_EXTRA_OPTIONS build/
-        - ninja -j${FDO_CI_CONCURRENT:-4} -C build/ install
-        - ninja -j${FDO_CI_CONCURRENT:-4} -C build/ test
+        - ninja -j${FDO_CI_CONCURRENT:-4} -C build/ dist
+        - PIGLIT_DIR=/root/piglit XTEST_DIR=/root/xts ninja -j${FDO_CI_CONCURRENT:-4} -C build/ test
         - .gitlab-ci/manpages-check
 
 meson-noglamor:

.gitlab-ci/debian-install.sh

@@ -5,7 +5,6 @@ set -o xtrace
 
 # Packages which are needed by this script, but not for the xserver build
 EPHEMERAL="
-	git
 	libcairo2-dev
 	libevdev-dev
 	libexpat-dev
@@ -27,6 +26,7 @@ apt-get install -y \
 	ca-certificates \
 	ccache \
 	flex \
+	git \
 	libaudit-dev \
 	libbsd-dev \
 	libcairo2 \