From: Andi Kleen <ak@muc.de>

Some configs didn't link anymore because they got references from
.altinstructions to __exit functions.  Fixing it at the linker level is not
easily possible.  This patch just discards .text.exit at runtime instead of
link time to avoid this.

It will also fix a related problem with .eh_frame in modern gcc (so far only
observed on x86-64, but could happen on i386 too)