[Bug sanitizer/64435] [5.0.0 Regression] Bootstrap failure in libsanitizer on AArch64 with Linux kernel <= 3.15

[david.abdurachmanov at gmail dot com]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=64435

--- Comment #1 from David Abdurachmanov <david.abdurachmanov at gmail dot com> 
---
Created attachment 34356
  --> https://gcc.gnu.org/bugzilla/attachment.cgi?id=34356&action=edit
RFC patch (tested)

Bootstrapped on aarch64-linux-gnu machine with F19 + 3.12 and on QEMU with F21
+ 3.17.