Gbuild explanation

Hello

I have a GNU make question, actually:

How this should be read ?
$(dir $(call gb_AutoInstallLibs_get_target,%)).dir :
        $(if $(wildcard $(dir $@)),,mkdir -p $(dir $@))

What I understand:
the $(call retrieves the variable content and pass the list of files in  
the current module directory as arguments. The first one is kept (from  
TargetLocations.mk, which says gb_AutoInstallLibs_get_target =  
$(WORKDIR)/AutoInstallLibs/$(1) )
We append a ".dir" to be sur to have a filename to give to $(dir, which  
will go up one level.
$@ will be the result of $(dir (something like $WORKDIR/AutoInstallLibs/ ?)
wildcard will test if the parent $WORKDIR exists, else we mkdir.

I know it seems silly to test $WORKDIR, so presumably I miss something in  
the $(call part, but I don't see what.

Thanks for the input

Best regards
--
Mat M