CI: Build `git describe` versioned snapshot tarballs

This:
 - modifies `configure.ac` to get a version number courtesy of `git`
   when `autoconf` is run
 - runs a `make dist` when all compilation targets succeed
 - makes the resulting tarball available as a build artifact
 - renames the various pipeline stages

.gitlab-ci.yml

@@ -9,42 +9,69 @@ variables:
   CONFIGURE_FULL: "--with-usb --enable-avahi --enable-pnm-backend"
 
 stages:
-  - lint
-  - build
+  - prepare
+  - compile
+  - archive
 
-lint:
-  stage: lint
+prepare:
+  image: $REGISTRY_HUB:debian-8-base
+  stage: prepare
   script:
   - find -path ./.git -prune -o -type f | xargs tools/style-check.sh
+  - sed -i '/^AC_INIT/s/,.*/,m4_esyscmd_s([git describe --dirty]),/' configure.ac
+  - autoconf --force
+  artifacts:
+    paths:
+    - configure
+    expire_in: 1 day
 
-.build_template: &build_definition
-  stage: build
+.compile_template: &compile_definition
+  stage: compile
   script:
   - ./configure $CONFIGURE_OPTS
   - make -j2 -k $MAKE_FLAGS
 
-build:debian-8-mini:
+compile:debian-8-mini:
   image: $REGISTRY_HUB:debian-8-mini
   variables:
     CONFIGURE_OPTS: "$CONFIGURE_MINI"
     MAKE_FLAGS: "CFLAGS=-Werror"
-  <<: *build_definition
+  <<: *compile_definition
 
-build:debian-8-full:
+compile:debian-8-full:
   image: $REGISTRY_HUB:debian-8-full
   variables:
     CONFIGURE_OPTS: "$CONFIGURE_MINI $CONFIGURE_FULL"
     MAKE_FLAGS: "CFLAGS=-Werror"
-  <<: *build_definition
+  <<: *compile_definition
+  cache:
+    untracked: true
+  artifacts:
+    paths:
+    - configure
+    expire_in: 1 day
 
-build:alpine-3.6-musl:
+compile:alpine-3.6-musl:
   image: $REGISTRY_HUB:alpine-3.6-musl
   variables:
     CONFIGURE_OPTS: "$CONFIGURE_MINI $CONFIGURE_FULL"
-  <<: *build_definition
+  <<: *compile_definition
 
-build:fedora-25-clang:
+compile:fedora-25-clang:
   image: $REGISTRY_HUB:fedora-25-clang
   variables:
     CONFIGURE_OPTS: "$CONFIGURE_MINI $CONFIGURE_FULL"
-  <<: *build_definition
+  <<: *compile_definition
+
+archive:
+  stage: archive
+  image: $REGISTRY_HUB:debian-8-full
+  dependencies:
+  - compile:debian-8-full
+  before_script:
+  - ./config.status --quiet || ./configure "$CONFIGURE_MINI"
+  script:
+  - make dist
+  artifacts:
+    paths:
+    - sane-backends-*.tar.gz

configure.ac

@@ -27,7 +27,7 @@ AS_IF([test x = "x`echo $VERSION | sed 's/[[.0-9]]//g'`"],
             [is_release=no])
 V_MAJOR=`echo $VERSION | $AWK -F. '{print $1}'`
 V_MINOR=`echo $VERSION | $AWK -F. '{print $2}'`
-V_REV=`echo $VERSION | $AWK -F. '{print $3}' | sed 's/[[^0-9]]//g'`;
+V_REV=`echo $VERSION | $AWK -F. '{print $3}' | sed 's/^\([[0-9]]*\).*/\1/'`;
 
 AC_DEFINE_UNQUOTED(SANE_DLL_V_MAJOR, $V_MAJOR, [SANE DLL major number])
 AC_DEFINE_UNQUOTED(SANE_DLL_V_MINOR, $V_MINOR, [SANE DLL minor number])