Copy stable/9 to releng/9.3 as part of the 9.3-RELEASE cycle.

Approved by: re (implicit)
Sponsored by: The FreeBSD Foundation

MFC 239138 (by andrew):

Import compiler-rt r160957.

This is mostly a no-op other than for ARM where it adds missing
__aeabi_mem* and __aeabi_*divmod functions. Even on ARM these will remain
unused until the rest of the ARM EABI code is merged.

MFC 245628 (by andrew):

Import compiler-rt r172839.

This brings in __aeabi_lcmp and __aeabi_ulcmp. It also fixes the spelling
of __aeabi_f2lz. Both changes originated on the arm_eabi project branch.

MFC 245641:

Add a newline at the end of the file to stop gcc from complaining

MFC 245642 (by andrew):

Don't use the pcs attribute on compilers that don't support it. We can
revert this when we stop supporting old versions of gcc.

Copy head to stable/9 as part of 9.0-RELEASE release cycle.

Approved by: re (implicit)

Upgrade libcompiler_rt from revision 117047 to 132478.

It seems there have only been a small amount to the compiler-rt source
code in the mean time. I'd rather have the code in sync as much as
possible by the time we release 9.0. Changes:

- The libcompiler_rt library is now dual licensed under both the
University of Illinois "BSD-Like" license and the MIT license.

- Our local modifications for using .hidden instead of .private_extern
have been upstreamed, meaning our changes to lib/assembly.h can now be
reverted.

- A possible endless recursion in __modsi3() has been fixed.

- Support for ARM EABI has been added, but it has no effect on FreeBSD
(yet).

- The functions __udivmodsi4 and __divmodsi4 have been added.

Requested by: many, including bf@ and Pedro Giffuni

Import compiler-rt r132478.