* util/grub-mkconfig_lib.in (grub_tab): New variable.

	* util/grub-mkconfig_lib.in (grub_tab): New variable.
	(grub_add_tab): New function.
	* util/grub.d/10_hurd.in: Replace \t with $grub_tab orgrub_add_tab.
	* util/grub.d/10_illumos.in: Likewise.
	* util/grub.d/10_kfreebsd.in: Likewise.
	* util/grub.d/10_linux.in: Likewise.
	* util/grub.d/10_netbsd.in: Likewise.
	* util/grub.d/10_windows.in: Likewise.
	* util/grub.d/10_xnu.in: Likewise.
	* util/grub.d/20_linux_xen.in: Likewise.
	* util/grub.d/30_os-prober.in: Likewise.