Help needed fixing linux-libre-5.2 on aarch64

[Mark H Weaver <mhw@netris.org>]

The 'kernel-updates' includes a preliminary commit to update linux-libre
to version 5.2.  Berlin has built it successfully on all supported
architectures except for aarch64, where it fails:

  https://ci.guix.gnu.org/build/1448778/details

I would be grateful if someone with access to aarch64 hardware could
debug this and propose a fix.  Until then, I'm reluctant to push this
update to 'master'.

See below for the relevant excerpt from the build log.

     Thanks,
       Mark


--8<---------------cut here---------------start------------->8---
  CC [M]  arch/arm64/lib/xor-neon.o
In file included from /gnu/store/im7irb1qnmvwypz53dxv5i75wy94dcz5-glibc-2.28/include/stdint.h:34:0,
                 from /gnu/store/7ykq1909hf7jgkvqcxdz7r0dglnbx005-gcc-7.4.0-lib/lib/gcc/aarch64-unknown-linux-gnu/7.4.0/include/arm_neon.h:33,
                 from ./arch/arm64/include/asm/neon-intrinsics.h:33,
                 from arch/arm64/lib/xor-neon.c:11:
/gnu/store/im7irb1qnmvwypz53dxv5i75wy94dcz5-glibc-2.28/include/bits/stdint-intn.h:27:19: error: conflicting types for 'int64_t'
 typedef __int64_t int64_t;
                   ^~~~~~~
In file included from ./include/linux/list.h:5:0,
                 from ./include/linux/module.h:9,
                 from arch/arm64/lib/xor-neon.c:10:
./include/linux/types.h:114:15: note: previous declaration of 'int64_t' was here
 typedef s64   int64_t;
               ^~~~~~~
In file included from /gnu/store/im7irb1qnmvwypz53dxv5i75wy94dcz5-glibc-2.28/include/stdint.h:37:0,
                 from /gnu/store/7ykq1909hf7jgkvqcxdz7r0dglnbx005-gcc-7.4.0-lib/lib/gcc/aarch64-unknown-linux-gnu/7.4.0/include/arm_neon.h:33,
                 from ./arch/arm64/include/asm/neon-intrinsics.h:33,
                 from arch/arm64/lib/xor-neon.c:11:
/gnu/store/im7irb1qnmvwypz53dxv5i75wy94dcz5-glibc-2.28/include/bits/stdint-uintn.h:27:20: error: conflicting types for 'uint64_t'
 typedef __uint64_t uint64_t;
                    ^~~~~~~~
In file included from ./include/linux/list.h:5:0,
                 from ./include/linux/module.h:9,
                 from arch/arm64/lib/xor-neon.c:10:
./include/linux/types.h:112:15: note: previous declaration of 'uint64_t' was here
 typedef u64   uint64_t;
               ^~~~~~~~
make[1]: *** [scripts/Makefile.build:285: arch/arm64/lib/xor-neon.o] Error 1
make: *** [Makefile:1071: arch/arm64/lib] Error 2
--8<---------------cut here---------------end--------------->8---