Move source tarball creation to prepare stage. Re !72

The build jobs use this tarball to exercise the build and only if all
builds pass will it be "archived".

.gitlab-ci.yml

@@ -14,22 +14,26 @@ stages:
   - archive
 
 prepare:
-  image: $REGISTRY_HUB:debian-9-mini
+  image: $REGISTRY_HUB:debian-9-full
   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
+  - ./autogen.sh
+  - ./configure
+  - make dist
   artifacts:
     paths:
-    - configure.ac
+    - sane-backends-*.tar.gz
     expire_in: 1 day
 
 .compile_template: &compile_definition
   stage: compile
   script:
-  - ./autogen.sh
-  - ./configure $CONFIGURE_OPTS
-  - make -j2 -k $MAKE_FLAGS
+  - mkdir build
+  - tar xaf sane-backends-*.tar.gz -C build --strip-components=1
+  - cd build && ./configure $CONFIGURE_OPTS
+  - make -C build -j2 -k $MAKE_FLAGS
 
 compile:debian-8-mini:
   image: $REGISTRY_HUB:debian-8-mini
@@ -59,12 +63,12 @@ compile:debian-9-full:
     MAKE_FLAGS: "CFLAGS=-Werror CXXFLAGS=-Werror"
   <<: *compile_definition
   after_script:
-  - make -C doc html-pages
-  - rm -rf lists && mkdir lists && mv doc/*.html lists/
-  - cd doc && doxygen doxygen-sanei.conf
+  - make -C build/doc html-pages
+  - rm -rf lists && mkdir lists && mv build/doc/*.html lists/
+  - cd build/doc && doxygen doxygen-sanei.conf && mv sanei-html ../../doc
   artifacts:
     paths:
-    - configure.ac
+    - sane-backends-*.tar.gz
     - lists
     - doc/sanei-html
     expire_in: 1 day
@@ -89,14 +93,8 @@ compile:alpine-3.9-musl:
 
 archive:
   stage: archive
-  image: $REGISTRY_HUB:debian-9-full
   dependencies:
   - compile:debian-9-full
-  before_script:
-  - ./autogen.sh
-  - ./configure "$CONFIGURE_MINI"
-  script:
-  - make dist
   artifacts:
     paths:
     - sane-backends-*.tar.gz