- first step in grace : compile without main

- added makefile to keep tmp file
- added builds and executable in gitignore

MakefileCommon

@@ -55,6 +55,7 @@ ifeq "$(D_OBJS)" "."
 else
   RM_OBJS     = rm -rf $(D_OBJS)
 endif
+F_DIFF        = tmp_$(NAME).c
 
 
 # - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - #
@@ -88,12 +89,15 @@ $(NAME): $(OBJS)
 leaks: $(NAME)
 	valgrind --leak-check=full --show-leak-kinds=all ./$(NAME)
 
-diff: $(NAME)
+diff_clean:
+	rm $(F_DIFF)
+diff_exec:
 	@echo $(CYAN)"compare source with output :"$(RESET)
-	./$(NAME) > tmp_$(NAME)
-	- diff --color tmp_$(NAME) $(SRCS); \
+	./$(NAME) > $(F_DIFF)
+	- diff --color $(F_DIFF) $(SRCS); \
 		if [  $$? -eq 0 ]; then echo $(GREEN)"Files $(NAME) and $(SRCS) are identical"$(RESET); else echo $(RED)":Files $(NAME) and $(SRCS) differ"$(RESET); fi
-	rm tmp_$(NAME)
+diff: $(NAME) diff_exec diff_clean
+diff_keep: $(NAME) diff_exec
 
 clean:
 	$(RM_OBJS)