Add check and error to the BUILD module if OBJDIR option is set but object...

Add check and error to the BUILD module if OBJDIR option is set but object filenames are not unique.

LUFA/Build/lufa.build.in

@@ -148,6 +148,11 @@ ifneq ($(OBJDIR),.)
    $(shell mkdir $(OBJDIR) 2> /dev/null)   
    VPATH           += $(dir $(SRC))
    OBJECT_FILES    := $(addprefix $(patsubst %/,%,$(OBJDIR))/, $(notdir $(OBJECT_FILES)))
+   
+   # Check if any object file (without path) appears more than once in the object file list
+   ifneq ($(words $(sort $(OBJECT_FILES))), $(words $(OBJECT_FILES)))
+       $(error Cannot build with OBJDIR parameter set - one or more object file name is not unique)
+   endif
 endif
 
 # Create a list of dependency files from the list of object files