Add missing *BSD copyright headers.

	* include/grub/aout.h: Add BSD licence.
	* include/grub/i386/bsd.h: Parts under different licences moved to ...
	* include/grub/i386/freebsd_linker.h: ... here,
	* include/grub/i386/freebsd_reboot.h: ... here,
	* include/grub/i386/netbsd_bootinfo.h: ... here,
	* include/grub/i386/netbsd_reboot.h: ... here,
	* include/grub/i386/openbsd_bootarg.h: ... here,
	* include/grub/i386/openbsd_reboot.h: ... and here. Added appropriate
	licence to each file.

	* conf/i386-pc.rmk (pkglib_MODULES): Add aout.mod _bsd.mod and bsd.mod.
	(aout_mod_SOURCES): New variable.
	(aout_mod_CFLAGS): Likewise.
	(aout_mod_LDFLAGS): Likewise.
	(_bsd_mod_SOURCES): New variable.
	(_bsd_mod_CFLAGS): Likewise.
	(_bsd_mod_LDFLAGS): Likewise.
	(bsd_mod_SOURCES): New variable.
	(bsd_mod_CFLAGS): Likewise.
	(bsd_mod_LDFLAGS): Likewise.

	* include/grub/aout.h: New file.

	* include/grub/i386/loader.h (grub_unix_real_boot): New function.

	* include/grub/i386/bsd.h: New file.

	* include/grub/i386/pc/init.h (grub_get_mmap_entry): Use EXPORT_FUNC
	to make it public.

	* kern/elf.c (grub_elf32_load): Get the physical address after the hook
	function is called, so that it's possible to change it inside the hook.
	(grub_elf64_load): Likewise.
	(grub_elf_file): Don't close the file if elf header is not found.
	(grub_elf_close): Close the file if grub_elf_file fails (The new
	grub_elf_file won't close it).
	(grub_elf32_size): Use NESTED_FUNC_ATTR for nested function calcsize.
	(grub_elf64_size): Likewise.

	* kern/i386/loader.S (grub_unix_real_boot): New function.

	* loader/aout.c: New file.

	* loader/i386/bsd.c: New file.

	* loader/i386/bsd_normal.c: New file.

	* loader/i386/pc/multiboot.c (grub_multiboot): Handle a.out format.

	* loader/multiboot2.c (grub_multiboot2): Reset grub_errno so that it
	can test othe formats.