e.g., kevin64-release:

https://ci.chromium.org/p/chromeos/builders/luci.chromeos.general/Prod/b8933573569094788816

  talloc-2.1.11: >>> Emerging (1 of 1) sys-libs/talloc-2.1.11::portage-stable for /build/kevin64/
  talloc-2.1.11:  * talloc-2.1.11.tar.gz BLAKE2B SHA512 size ;-) ...                      [ ok ]
  talloc-2.1.11:  * Running stacked hooks for pre_pkg_setup
  talloc-2.1.11:  *    sysroot_build_bin_dir ...
  talloc-2.1.11:  [ ok ]
  talloc-2.1.11:  * Running stacked hooks for post_pkg_setup
  talloc-2.1.11:  *    python_eclass_hack ...
  talloc-2.1.11:  [ ok ]
  talloc-2.1.11:  * Running stacked hooks for pre_src_unpack
  talloc-2.1.11:  *    python_multilib_setup ...
  talloc-2.1.11:  [ ok ]
  talloc-2.1.11: >>> Unpacking source...
  talloc-2.1.11: >>> Unpacking talloc-2.1.11.tar.gz to /build/kevin64/tmp/portage/sys-libs/talloc-2.1.11/work
  talloc-2.1.11: >>> Source unpacked in /build/kevin64/tmp/portage/sys-libs/talloc-2.1.11/work
  talloc-2.1.11:  * Running stacked hooks for post_src_unpack
  talloc-2.1.11:  *    asan_init ...
  talloc-2.1.11:  [ ok ]
  talloc-2.1.11:  * Running stacked hooks for pre_src_prepare
  talloc-2.1.11:  *    cross ...
  talloc-2.1.11:  * ERROR: sys-libs/talloc-2.1.11::portage-stable failed (prepare phase):
  talloc-2.1.11:  *   talloc-2.1.11 does not support cross-compiling for arm64
  talloc-2.1.11:  * 
  talloc-2.1.11:  * Call stack:
  talloc-2.1.11:  *        ebuild.sh, line  133:  Called pre_src_prepare
  talloc-2.1.11:  *      environment, line 2034:  Called cros_stack_hooks 'pre_src_prepare'
  talloc-2.1.11:  *   profile.bashrc, line   86:  Called cros_pre_src_prepare_cross
  talloc-2.1.11:  *    talloc.bashrc, line   22:  Called die
  talloc-2.1.11:  * The specific snippet of code:
  talloc-2.1.11:  *   			die "${P} does not support cross-compiling for ${ARCH}"
  talloc-2.1.11:  * 
  talloc-2.1.11:  * If you need support, post the output of `emerge --info '=sys-libs/talloc-2.1.11::portage-stable'`,
  talloc-2.1.11:  * the complete build log and the output of `emerge -pqv '=sys-libs/talloc-2.1.11::portage-stable'`.
  talloc-2.1.11:  * The complete build log is located at '/build/kevin64/tmp/portage/logs/sys-libs:talloc-2.1.11:20181004-202107.log'.
  talloc-2.1.11:  * For convenience, a symlink to the build log is located at '/build/kevin64/tmp/portage/sys-libs/talloc-2.1.11/temp/build.log'.
  talloc-2.1.11:  * The ebuild environment file is located at '/build/kevin64/tmp/portage/sys-libs/talloc-2.1.11/temp/environment'.
  talloc-2.1.11:  * Working directory: '/build/kevin64/tmp/portage/sys-libs/talloc-2.1.11/work/talloc-2.1.11'
  talloc-2.1.11:  * S: '/build/kevin64/tmp/portage/sys-libs/talloc-2.1.11/work/talloc-2.1.11'
  talloc-2.1.11: >>> Failed to emerge sys-libs/talloc-2.1.11 for /build/kevin64/, Log file:
  talloc-2.1.11: >>>  '/build/kevin64/tmp/portage/logs/sys-libs:talloc-2.1.11:20181004-202107.log'
  talloc-2.1.11: 
  talloc-2.1.11:  * Messages for package sys-libs/talloc-2.1.11 merged to /build/kevin64/:
  talloc-2.1.11: 
  talloc-2.1.11:  * ERROR: sys-libs/talloc-2.1.11::portage-stable failed (prepare phase):
  talloc-2.1.11:  *   talloc-2.1.11 does not support cross-compiling for arm64
  talloc-2.1.11:  * 
  talloc-2.1.11:  * Call stack:
  talloc-2.1.11:  *        ebuild.sh, line  133:  Called pre_src_prepare
  talloc-2.1.11:  *      environment, line 2034:  Called cros_stack_hooks 'pre_src_prepare'
  talloc-2.1.11:  *   profile.bashrc, line   86:  Called cros_pre_src_prepare_cross
  talloc-2.1.11:  *    talloc.bashrc, line   22:  Called die
  talloc-2.1.11:  * The specific snippet of code:
  talloc-2.1.11:  *   			die "${P} does not support cross-compiling for ${ARCH}"
  talloc-2.1.11:  * 
  talloc-2.1.11:  * If you need support, post the output of `emerge --info '=sys-libs/talloc-2.1.11::portage-stable'`,
  talloc-2.1.11:  * the complete build log and the output of `emerge -pqv '=sys-libs/talloc-2.1.11::portage-stable'`.
  talloc-2.1.11:  * The complete build log is located at '/build/kevin64/tmp/portage/logs/sys-libs:talloc-2.1.11:20181004-202107.log'.
  talloc-2.1.11:  * For convenience, a symlink to the build log is located at '/build/kevin64/tmp/portage/sys-libs/talloc-2.1.11/temp/build.log'.
  talloc-2.1.11:  * The ebuild environment file is located at '/build/kevin64/tmp/portage/sys-libs/talloc-2.1.11/temp/environment'.
  talloc-2.1.11:  * Working directory: '/build/kevin64/tmp/portage/sys-libs/talloc-2.1.11/work/talloc-2.1.11'
  talloc-2.1.11:  * S: '/build/kevin64/tmp/portage/sys-libs/talloc-2.1.11/work/talloc-2.1.11'