variable hooks & global variables

[Robert Millan]

When you set a variable hook (grub_register_variable_hook), this hook isn't
preserved after someone (e.g. configfile command) opens a new context
(grub_env_context_open), unless the variable has been set as global
(grub_env_export).

Is this what we want?

The only current user of variable hooks is "root" variable, and that hook
contains a sanity check that seems to be more suitable for global scope.

The color-related variables for which I wanted to add hooks would also
like to keep their hooks across contexts.

One option is to export these variables, or to modify grub_env_context_open()
to preserve hooks as well as exported variables.  I'm more inclined for the
latter.

Comments?

-- 
Robert Millan

<GPLv2> I know my rights; I want my phone call!
<DRM> What use is a phone call, if you are unable to speak?
(as seen on /.)