Append gitlabci build number to package version field

For more info, see
https://gitlab.sol1.net/salsa/salsa/-/blob/master/RELEASE.md

.gitlab-ci.yml

@@ -6,6 +6,8 @@ package:
   image: debian
   stage: package
   script:
+    - cp dist/control dist/control.skel
+    - dist/bumpver dist/control.skel > dist/control
     - debian/mkdeb
   artifacts:
     paths:

debian/bumpver

+#!/usr/bin/awk -f
+
+# bumpver prints a modified debian package control file based on
+# environment variables set from Gitlab CI. If a tagged revision is
+# being built, then the Version field is the plain semver. Otherwise,
+# the version from the control file has the Gitlab CI pipeline ID
+# appended.
+
+/Version/ {
+	if (ENVIRON["CI_COMMIT_TAG"]) {
+		# strip "v" prefix from tag
+		semver = ENVIRON["CI_COMMIT_TAG"]
+		sub("^v", "", semver)
+		printf "%s %s\n", $1, semver
+		next
+	}
+	printf("%s-%d\n", $0, ENVIRON["CI_PIPELINE_IID"])
+	next
+}
+{
+	print
+}