Add grub_util_disable_fd_syncs call to turn grub_util_fd_sync calls into
no-ops, and use it in programs that copy files but do not need to take
special care to sync writes (grub-mknetdir, grub-rescue,
grub-mkstandalone).
On my laptop, this reduces partmap_test's runtime from 1236 seconds to
204 seconds.
* include/grub/util/install.h (GRUB_INSTALL_OPTIONS): Add
--locale-directory option.
(enum grub_install_options): Add
GRUB_INSTALL_OPTIONS_LOCALE_DIRECTORY.
* util/grub-install-common.c (grub_install_help_filter): Handle
GRUB_INSTALL_OPTIONS_LOCALE_DIRECTORY.
(grub_install_parse): Likewise.
(get_localedir): New function to check for a user-provided option
before trying grub_util_get_localedir.
(copy_locales): Use get_localedir rather than
grub_util_get_localedir. Handle differing locale directory layouts.
(grub_install_copy_files): Likewise.
the function of these files exceeds what can be sanely handled in shell
in posix-comaptible way. Also writing it in C extends the functionality
to non-UNIX-like OS and minimal environments.
