Re: kbuild: fix section mismatch check for vmlinux

["Jan Beulich" <jbeulich@novell.com>]

>vmlinux does not contain relocation entries which is
>used by the section mismatch checks.
>Reported by: Atsushi Nemoto <anemo@mba.ocn.ne.jp>
>
>Use the individual objects as inputs to overcome
>this limitation.
>In modpost check the .o files and skip non-ELF files.
>
>Signed-off-by: Sam Ravnborg <sam@ravnborg.org>

This still doesn't appear to catch all cases - since the checking logic works
on a per-module basis, references between the individual .o files aren't
being checked. A current instance where this is visible is x86-64's recently
added alloc_bootmem_high_node (non-__init, in arch/x86_64/mm/built-in.o)
calling __alloc_bootmem_core (__init, in mm/built-in.o). I suppose there's
no way around linking $(KBUILD_VMLINUX_OBJS) into vmlinux.o, and
checking that file instead.

Jan