* include/grub/err.h (grub_err_t): Add `GRUB_ERR_MENU'.
* kern/env.c (grub_env_unset): Don't free the member `value' when
the type is GRUB_ENV_VAR_DATA, in this case it's a user defined
pointer.
* normal/main.c (current_menu): Removed.
(free_menu): Unset the `menu' environment variable.
(grub_normal_menu_addentry): Make use of the environment variable
`menu', instead of using the global `current_menu'. Allocate
memory for the sourcecode of this entry.
(read_config_file): New argument `nested', changed all callers.
Only in the case of a new context, initialize a new menu. Set the
`menu' environment variable.
(grub_normal_execute): Don't set and unset the environment
variable `menu' here anymore. Only free the menu when leaving the
context.
* util/i386/pc/biosdisk.c (linux_find_partition): Fixed a memory
leak.