+val.%:
+ @$(if $(filter undefined,$(origin $*)),\
+ echo "$* undefined" >&2, \
+ echo '$(subst ','"'"',$($*))' \
+ )
+
+var.%:
+ @$(if $(filter undefined,$(origin $*)),\
+ echo "$* undefined" >&2, \
+ echo "$*='"'$(subst ','"'\"'\"'"',$($*))'"'" \
+ )
+