fix failing build because of BUILD_DATE var name collision

.gitlab-ci.yml

@@ -21,8 +21,8 @@ generate_date:
 .target:
   stage: build
   script:
-    - make -C gluon update GLUON_SITEDIR="$CI_PROJECT_DIR" BUILD_DATE=$(cat build.date)
-    - make -C gluon GLUON_SITEDIR="$CI_PROJECT_DIR" GLUON_TARGET="$GLUON_TARGET" GLUON_BRANCH=stable BUILD_DATE=$(cat build.date) V=1 -j`nproc`
+    - make -C gluon update GLUON_SITEDIR="$CI_PROJECT_DIR" FFS_BUILD_DATE=$(cat build.date)
+    - make -C gluon GLUON_SITEDIR="$CI_PROJECT_DIR" GLUON_TARGET="$GLUON_TARGET" GLUON_BRANCH=stable FFS_BUILD_DATE=$(cat build.date) V=1 -j`nproc`
   except:
     - tags
   artifacts: 

site.mk

@@ -81,9 +81,9 @@ endif
 
 DEFAULT_BUILD_DATE := $(shell date '+%Y-%m-%d')
 
-BUILD_DATE ?= $(DEFAULT_BUILD_DATE)
+FFS_BUILD_DATE ?= $(DEFAULT_BUILD_DATE)
 
-DEFAULT_GLUON_RELEASE := 1.9+$(BUILD_DATE)-g.$(shell git -C $(GLUON_SITEDIR)/gluon log --pretty=format:'%h' -n 1)-s.$(shell git -C $(GLUON_SITEDIR) log --pretty=format:'%h' -n 1)
+DEFAULT_GLUON_RELEASE := 1.9+$(FFS_BUILD_DATE)-g.$(shell git -C $(GLUON_SITEDIR)/gluon log --pretty=format:'%h' -n 1)-s.$(shell git -C $(GLUON_SITEDIR) log --pretty=format:'%h' -n 1)
 
 GLUON_LANGS := de en