simple_cmd_builtin() done.

+ exec_cmd_line.c split in multiples files

Makefile

@@ -34,7 +34,8 @@ SRCS =	main.c init.c free.c generic.c \
 		words_expansions.c expand_token.c rejoin_after_expand.c new_token_for_each_field.c \
 		ft_split_quotes.c ft_strdup_quotes.c \
 		redirections.c here_doc.c \
-		exec_cmd_line.c \
+		exec_cmd_line.c pipeline.c \
+		find_access.c subshell_exec.c subshell_wait.c simple_cmd_builtin.c \
 		cd.c pwd.c export.c unset.c exit.c env.c echo.c
 
 DIR_OBJS = builds