ci: create build logs and collect as artifacts

To diagnore the intermittent perl build issue we see, collect the build
log archive and store it as an artifact.

.gitlab-ci.yml

@@ -69,11 +69,12 @@ build-target:
   except:
     - tags
   script:
-    - make -C gluon GLUON_SITEDIR="$CI_PROJECT_DIR" GLUON_TARGET="$TARGET" GLUON_AUTOUPDATER_BRANCH=stable GLUON_AUTOUPDATER_ENABLED=1 FFS_BUILD_DATE=$(cat build.date) BROKEN="$BROKEN" V=1 -j`nproc`
+    - make -C gluon GLUON_SITEDIR="$CI_PROJECT_DIR" GLUON_TARGET="$TARGET" GLUON_AUTOUPDATER_BRANCH=stable GLUON_AUTOUPDATER_ENABLED=1 FFS_BUILD_DATE=$(cat build.date) BROKEN="$BROKEN" V=1 -j`nproc` BUILD_LOG=1
   artifacts: 
     paths:
       - gluon/output/
     expire_in: 1 day
+    when: always
   cache: []
   parallel:
     matrix: