* grub-core/Makefile.core.def (kernel): Add kern/emu/argp_common.c on
emu.
* util/argp_common.c: Rename to ...
* grub-core/kern/emu/argp_common.c: ... this. All users updated.
Add missing includes.
* grub-core/kern/emu/main.c: Convert to argp.
* po/POTFILES.in: Regenerate.
* util/grub-install.in (usage): Make first letter lowcase in messages
for uniformity.
* util/grub-setup.c (options): Likewise.
