GNU Arm Embedded Toolchain 10.3-2021.10

This release includes bare metal pre-built binaries for AArch32 EABI targets,
which can be hosted on:
* Windows 10 or later on IA-32 or x86_64
* Mac OS X 10.14 or later on x86_64
* Linux on x86_64
  These toolchains are built on and for Ubuntu 16.04 on x86_64,
  and will likely also be useable on OS versions:
  - later than Ubuntu 16.04
  - RHEL 8
* Linux on AArch64
  These toolchains are built on and for Ubuntu 18.04 on AArch64,
  and will likely also be useable on OS versions:
  - later than Ubuntu 18.04
  - RHEL 8

For Windows, the binaries are provided with an installer and as a zip file.
For Linux, the binaries are provided as tarball files.
For Mac OS X, the binaries are provided as tarball and pkg files.

The release also contains source code package (together with build scripts and
instructions to setup the build environment), which is composed of:

  * gcc : refs/vendors/ARM/heads/arm-10
    git://gcc.gnu.org/git/gcc.git commit a7eb0564c3060418b5ca68c2806ad74f73384fd0

  * binutils : binutils-2_36-branch
    git://sourceware.org/git/binutils-gdb.git commit a7eb3ff36cebc093af6658049e03d63579dade86

  * newlib and newlib-nano : 2a3a03972b35377aef8d3d52d873ac3b8fcc512c
    git://sourceware.org/git/newlib-cygwin.git commit 2a3a03972b35377aef8d3d52d873ac3b8fcc512c

  * gdb : gdb-10-branch
    git://sourceware.org/git/binutils-gdb.git commit abbf09189720ddc14fe71d0afdfa7653b8c67b5d

Note that some or all of the following prerequisites are downloaded when
building from source:

  * EnvVarUpdate NSIS script :
    http://nsis.sourceforge.net/mediawiki/images/a/ad/EnvVarUpdate.7z

  * expat 2.1.1 :
    https://downloads.sourceforge.net/project/expat/expat/2.1.1/expat-2.1.1.tar.bz2

  * gmp 6.1.0 :
    https://gmplib.org/download/gmp/gmp-6.1.0.tar.bz2

  * isl 0.18 :
    https://sourceforge.net/projects/libisl/files

  * libelf 0.8.13 :
    https://fossies.org/linux/misc/old/libelf-0.8.13.tar.gz

  * libiconv 1.15 :
    https://ftp.gnu.org/pub/gnu/libiconv/libiconv-1.15.tar.gz

  * mpc 1.0.3 :
    ftp://ftp.gnu.org/gnu/mpc/mpc-1.0.3.tar.gz

  * mpfr 3.1.4 :
    http://www.mpfr.org/mpfr-3.1.4/mpfr-3.1.4.tar.bz2

  * python 2.7.7 :
    https://www.python.org/ftp/python/2.7.7/python-2.7.7.msi

  * zlib 1.2.8 :
    http://www.zlib.net/fossils/zlib-1.2.8.tar.gz

Features:
* All GCC 10.3 features

Tests:
* Targets:
  + Variety of Cortex-M0/M0+/M3/M4/M7/A9 boards
  + Qemu
  + Arm Fast Models

Notable changes in 10.3-2021.10 release:

* Added mitigation for the VLLDM instruction security vulnerability
  described in:
  https://developer.arm.com/support/arm-security-updates/vlldm-instruction-security-vulnerability

Known issues:
* Doing IPA on CMSE generates a linker error:
The linker will error out when resulting object file contains a symbol for
the clone function with the __acle_se prefix that has a non-local binding.
  Issue occurs when compiling binaries for M-profile Secure Extensions where
the compiler may decide to clone a function with the cmse_nonsecure_entry
attribute.
  Although cloning nonsecure entry functions is legal, as long as the clone
is only used inside the secure application, the clone function itself should
not be seen as a secure entry point and so it should not have the __acle_se
prefix.
  A possible workaround for this is to add a 'noclone' attribute to
functions with the 'cmse_nonsecure_entry'. This will prevent GCC from cloning
such functions.

* GCC can hang or crash if the input source code uses MVE Intrinsics
polymorphic variants in a nested form. The depth of nesting that
triggers this issue might vary depending on the host machine.
This behaviour is observed when nesting 7 times or more on a high-end
workstation. On less powerful machines, this behaviour might be
observed with fewer levels of nesting. This issue is reported in
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=91937