fix: Makefile portability

Makefile

@@ -3,10 +3,15 @@ LIBFT = libft.a
 SRCS = minishell.c lexer.c parser.c utils.c caller.c built-in.c env.c
 OBJS = ${SRCS:.c=.o}
 
-#READLINE_INC = ~/.brew/opt/readline/include
-#LIB = -L ~/.brew/lib -lreadline -L ~/.brew/lib -lhistory -L. -lft
 
+UNAME_S := $(shell uname -s)
+ifeq ($(UNAME_S), Linux)
 	LIB = -lreadline -lhistory -L. -lft
+endif
+ifeq ($(UNAME_S), Darwin)
+	READLINE_INC = -I ~/.brew/opt/readline/include
+	LIB = -L ~/.brew/lib -lreadline -L ~/.brew/lib -lhistory -L. -lft
+endif
 
 $(NAME):	$(LIBFT) $(OBJS)
 		gcc ${OBJS} ${LIB} -o ${NAME}
@@ -18,7 +23,7 @@ $(LIBFT):
 all:	$(NAME)
 
 %.o:	%.c
-			gcc -Werror -Wextra -Wall -g -c $< # -I ${READLINE_INC} #for rl_replace_line
+			gcc -Werror -Wextra -Wall -g -c $< ${READLINE_INC}
 
 clean:
 		rm -rf ${OBJS}