After updating to next-release, I ran emerge -e world and got this error when it was emerging python-3.7.10:

{{
x86_64-pc-linux-gnu-ar rcs libpython3.7m.a Modules/getbuildinfo.o Parser/acceler.o Parser/grammar1.o Parser/listnode.o Parser/node.o Parser/parser.o Parser/bitset.o Parser/metagrammar.o Parser/firstsets.o Parser/grammar.o Parser/pgen.o Parser/myreadline.o Parser/parsetok.o Parser/tokenizer.o Objects/abstract.o Objects/accu.o Objects/boolobject.o Objects/bytes_methods.o Objects/bytearrayobject.o Objects/bytesobject.o Objects/call.o Objects/cellobject.o Objects/classobject.o Objects/codeobject.o Objects/complexobject.o Objects/descrobject.o Objects/enumobject.o Objects/exceptions.o Objects/genobject.o Objects/fileobject.o Objects/floatobject.o Objects/frameobject.o Objects/funcobject.o Objects/iterobject.o Objects/listobject.o Objects/longobject.o Objects/dictobject.o Objects/odictobject.o Objects/memoryobject.o Objects/methodobject.o Objects/moduleobject.o Objects/namespaceobject.o Objects/object.o Objects/obmalloc.o Objects/capsule.o Objects/rangeobject.o Objects/setobject.o Objects/sliceobject.o Objects/structseq.o Objects/tupleobject.o Objects/typeobject.o Objects/unicodeobject.o Objects/unicodectype.o Objects/weakrefobject.o Python/_warnings.o Python/Python-ast.o Python/asdl.o Python/ast.o Python/ast_opt.o Python/ast_unparse.o Python/bltinmodule.o Python/ceval.o Python/compile.o Python/codecs.o Python/dynamic_annotations.o Python/errors.o Python/frozenmain.o Python/future.o Python/getargs.o Python/getcompiler.o Python/getcopyright.o Python/getplatform.o Python/getversion.o Python/graminit.o Python/import.o Python/importdl.o Python/marshal.o Python/modsupport.o Python/mysnprintf.o Python/mystrtoul.o Python/pathconfig.o Python/peephole.o Python/pyarena.o Python/pyctype.o Python/pyfpe.o Python/pyhash.o Python/pylifecycle.o Python/pymath.o Python/pystate.o Python/context.o Python/hamt.o Python/pythonrun.o Python/pytime.o Python/bootstrap_hash.o Python/structmember.o Python/symtable.o Python/sysmodule.o Python/thread.o Python/traceback.o Python/getopt.o Python/pystrcmp.o Python/pystrtod.o Python/pystrhex.o Python/dtoa.o Python/formatter_unicode.o Python/fileutils.o Python/dynload_shlib.o Modules/config.o Modules/getpath.o Modules/main.o Modules/gcmodule.o Modules/posixmodule.o Modules/errnomodule.o Modules/pwdmodule.o Modules/_sre.o Modules/_codecsmodule.o Modules/_weakref.o Modules/_functoolsmodule.o Modules/_operator.o Modules/_collectionsmodule.o Modules/_abc.o Modules/itertoolsmodule.o Modules/atexitmodule.o Modules/signalmodule.o Modules/_stat.o Modules/timemodule.o Modules/_threadmodule.o Modules/_localemodule.o Modules/_iomodule.o Modules/iobase.o Modules/fileio.o Modules/bytesio.o Modules/bufferedio.o Modules/textio.o Modules/stringio.o Modules/zipimport.o Modules/faulthandler.o Modules/_tracemalloc.o Modules/hashtable.o Modules/symtablemodule.o Modules/xxsubtype.o Python/frozen.o
x86_64-pc-linux-gnu-gcc pthread -shared -Wl,-O1 -Wl,sort-common -Wl,as-needed -L. -Wl,-no-as-needed -o libpython3.so -Wl,-hlibpython3.so libpython3.7m.so
x86_64-pc-linux-gnu-gcc pthread -Wl,-O1 -Wl,sort-common -Wl,-as-needed -L. -Xlinker -export-dynamic -o python Programs/python.o -L. -lpython3.7m -lcrypt -lpthread -ldl -lutil -lm
x86_64-pc-linux-gnu-gcc pthread -Wl,-O1 -Wl,sort-common -Wl,-as-needed -L. -Xlinker -export-dynamic -o Programs/_testembed Programs/_testembed.o -L. -lpython3.7m -lcrypt -lpthread -ldl -lutil -lm
LD_LIBRARY_PATH=/var/tmp/portage/dev-lang/python-3.7.10/work/Python-3.7.10 ./python -E -S -m sysconfig --generate-posix-vars ;\
if test $? -ne 0 ; then \
echo "generate-posix-vars failed" ; \
rm -f ./pybuilddir.txt ; \
exit 1 ; \
fi
LD_LIBRARY_PATH=/var/tmp/portage/dev-lang/python-3.7.10/work/Python-3.7.10 CC='x86_64-pc-linux-gnu-gcc pthread' LDSHARED='x86_64-pc-linux-gnu-gcc -pthread -shared -Wl,-O1 -Wl,sort-common -Wl,-as-needed -L. ' CFLAGS='-Wno-unused-result -Wsign-compare -DNDEBUG -march=westmere -O2 -pipe -O3 -fno-semantic-interposition -fwrapv ' _TCLTK_INCLUDES='' _TCLTK_LIBS='' ./python -E ./setup.py build
Traceback (most recent call last):
File "./setup.py", line 10, in <module>
from distutils import log
File "/usr/lib/python3.7/site-packages/distutils_hack/init_.py", line 92, in create_module
return importlib.import_module('setuptools._distutils')
File "/var/tmp/portage/dev-lang/python-3.7.10/work/Python-3.7.10/Lib/importlib/_init_.py", line 127, in import_module
return _bootstrap._gcd_import(name[level:], package, level)
File "/usr/lib/python3.7/site-packages/setuptools/_init_.py", line 8, in <module>
import _distutils_hack.override # noqa: F401
File "/usr/lib/python3.7/site-packages/_distutils_hack/override.py", line 1, in <module>
_import_('_distutils_hack').do_override()
File "/usr/lib/python3.7/site-packages/distutils_hack/init_.py", line 73, in do_override
ensure_local_distutils()
File "/usr/lib/python3.7/site-packages/distutils_hack/init_.py", line 60, in ensure_local_distutils
core = importlib.import_module('distutils.core')
File "/var/tmp/portage/dev-lang/python-3.7.10/work/Python-3.7.10/Lib/importlib/_init_.py", line 127, in import_module
return _bootstrap._gcd_import(name[level:], package, level)
File "/usr/lib/python3.7/site-packages/setuptools/_distutils/core.py", line 17, in <module>
from distutils.dist import Distribution
File "/usr/lib/python3.7/site-packages/setuptools/_distutils/dist.py", line 19, in <module>
from distutils.util import check_environ, strtobool, rfc822_escape
File "/usr/lib/python3.7/site-packages/setuptools/_distutils/util.py", line 14, in <module>
from distutils.spawn import spawn
File "/usr/lib/python3.7/site-packages/setuptools/_distutils/spawn.py", line 11, in <module>
import subprocess
File "/var/tmp/portage/dev-lang/python-3.7.10/work/Python-3.7.10/Lib/subprocess.py", line 152, in <module>
import _posixsubprocess
ModuleNotFoundError: No module named '_posixsubprocess'
make: *** [Makefile:628: sharedmods] Error 1

• ERROR: dev-lang/python-3.7.10::python-kit failed (compile phase):
• emake failed
• If you need support, post the output of `emerge --info '=dev-lang/python-3.7.10::python-kit'`,
• the complete build log and the output of `emerge -pqv '=dev-lang/python-3.7.10::python-kit'`.
• The complete build log is located at '/var/tmp/portage/dev-lang/python-3.7.10/temp/build.log'.
• The ebuild environment file is located at '/var/tmp/portage/dev-lang/python-3.7.10/temp/environment'.
• Working directory: '/var/tmp/portage/dev-lang/python-3.7.10/work/Python-3.7.10'
• S: '/var/tmp/portage/dev-lang/python-3.7.10/work/Python-3.7.10'
  }}