Build a kernel deb as well

This uses our packaging instead of plain `make bindeb-pkg` so it can
easily be tested on devices.

We add the current topmost commit to the changelog and add +gitlabci1 to
the version number so it becomes easy to identify.
Signed-off-by: Guido Günther <guido.gunther@puri.sm>

.gitlab-ci.yml

 variables:
-  DEPS: >
-    build-essential gcc-aarch64-linux-gnu make device-tree-compiler
-    bison flex bc libssl-dev
+  WORKING_DIR: $CI_PROJECT_DIR/debian/output
 
 before_script:
+  - echo "man-db man-db/auto-update boolean false" | debconf-set-selections
   - export DEBIAN_FRONTEND=noninteractive
   - apt-get -y update
-  - apt-get -y install $DEPS
+  - apt-get -y build-dep .
+  - apt-get -y install build-essential devscripts
 
 .tags: &tags
   tags:
@@ -29,3 +29,18 @@ build:aarch64:
       - arch/arm64/boot/dts/freescale/imx8mq-librem5.dtb
       - modules/
     expire_in: 1 week
+
+build:deb:
+  <<: *tags
+  stage: build
+  script:
+    - git clean -dfx
+    - git checkout -f
+    - rm -rf "${WORKING_DIR}"; mkdir -p "${WORKING_DIR}"
+    - dch -l +gitlabci "Gitlab ci build of ${CI_COMMIT_SHA}"
+    - dpkg-buildpackage -j4 -uc -us -B  --host-arch=arm64
+    - cp -l ../*.deb ../*.changes ../*.buildinfo "${WORKING_DIR}/"
+  artifacts:
+    paths:
+      - "${WORKING_DIR}"
+    expire_in: 1 week