* kern/env.c (struct grub_env_context): Removed "sorted". Renamed
"next" to "prev" for readability.
(struct grub_env_sorted_var): New struct.
(grub_env_context): Renamed to ...
(initial_context): ... this.
(grub_env_var_context): Renamed to ...
(current_context): ... this.
(grub_env_find): Look only at CURRENT_CONTEXT.
(grub_env_context_open): Rewritten to copy exported variables from
previous context.
(grub_env_context_close): Rewritten according to the new
scheme. Also, add an assertion to prevent the initial context from
removed.
(grub_env_insert): Removed the code for the sorted list.
(grub_env_remove): Likewise.
(grub_env_export): Simply mark the variable with
GRUB_ENV_VAR_GLOBAL.
(grub_env_set): A cosmetic change for naming consistency.
(grub_env_get): Likewise.
(grub_env_unset): Likewise.
(grub_env_iterate): Rewritten to sort variables within this
function.
(grub_register_variable_hook): Fixed for naming consistency. Call
grub_env_find again, only if NAME is not found at the first time.
(mangle_data_slot_name): New function.
(grub_env_set_data_slot): Likewise.
(grub_env_get_data_slot): Likewise.
(grub_env_unset_data_slot): Likewise.
* include/grub/env.h (grub_env_var_type): New enum.
(GRUB_ENV_VAR_LOCAL): New constant.
(GRUB_ENV_VAR_GLOBAL): Likewise.
(GRUB_ENV_VAR_DATA): Likewise.
(struct grub_env_var): Removed "sort_next" and "sort_prevp". Added
"type".
(grub_env_set): Replace VAR with NAME for consistency.
(grub_register_variable_hook): Likewise.
(grub_env_export): Specify the name of the argument.
(grub_env_set_data_slot): New prototype.
(grub_env_get_data_slot): Likewise.
(grub_env_unset_data_slot): Likewise.