x86: Deprecate a.out support

Linux supports ELF binaries for ~25 years now. a.out coredumping has bitrotten quite significantly and would need some fixing to get it into shape again but considering how even the toolchains cannot create a.out executables in its default configuration, let’s deprecate a.out support and remove it a couple of releases later, instead. Signed-off-by: Borislav Petkov Acked-by: Richard Weinberger Cc: Al Viro Cc: Anton Ivanov Cc: Jann Horn Cc: Cc: Cc: lkml Cc: Matthew Wilcox Cc: Thomas Gleixner Cc: Signed-off-by: Linus Torvalds old a.out binaries in the 32bit emulation.

Source: git.kernel.org