Check for the existance of variable.

[PATTON, BILLY \(SBCSI\)]

Ok Paul,
 commands are shell syntax and make file is for make syntax.  I cannot
check for the existence
of a make variable in the commands of a rule.  So with that said I must
check for the existence
of the variable before I create the rule.

Here's what I have:
$(foreach flow,refresh real_refresh, \
        $(foreach sub,pub shr extra, \
                $(foreach proj,$(PROJECTS),\
                        $(foreach bb,$(BB+$(proj)),\
                                $(eval $(call
refresh_proj_bb_sub,$(flow),$(proj),$(bb),$(sub)))))))

The variable I need : proj has 7 values, bb may have 1 to 80 names,
depends on proj
REFRESH+proj+bb+pub
  
Steps I would need to create this
1. create the string
   $(call merge,+,$(call uc,$(flow)) $(proj) $(bb) $(sub))
2. find the origin of the string
   $(origin $(call merge,+,$(call uc,$(flow)) $(proj) $(bb) $(sub))
3. find the string "file"
   $(findstring file,$(origin $(call merge,+,$(call uc,$(flow)) $(proj)
$(bb) $(sub))
4 do if then
   $(if $(findstring file,$(origin $(call merge,+,$(call uc,$(flow))
$(proj) $(bb) $(sub))
   then do the eval.

So I believe I would need something like
$(foreach flow,refresh real_refresh, \
        $(foreach sub,pub shr extra, \
                $(foreach proj,$(PROJECTS),\
                        $(foreach bb,$(BB+$(proj)),\
                                $(if $(findstring file,$(origin $(call
$(merge +,$(call uc,$(flow)) $(proj) $(bb) $(sub)))))
                                  ,$(eval $(call
refresh_proj_bb_sub,$(flow),$(proj),$(bb),$(sub))))))
missing lots of  ) parens :)


I'll be testing this, but if you see anything wrong with my logic please
tell me :)