Updated version based on principles:

• Should not specify --with(out)-xyz in help string, it's implied by default
• Sentences should start with lowercase (as autoconf generates the builtin string with lower case)
• --with-xyx=VALUE will be described as "overriding"
• --with-xyz will be described as "enabling" said feature
• Mac flags should have the same descriptions as what is in Mac/README.rst
• Default value should be in brackets (if known)
• Enumerated options should be shown as =VAL1|VAL2 or [=VAL1|VAL2] if optional

 Optional Features:
  --disable-option-checking  ignore unrecognized --enable/--with options
  --disable-FEATURE       do not include FEATURE (same as --enable-FEATURE=no)
  --enable-FEATURE[=ARG]  include FEATURE [ARG=yes]
  --enable-universalsdk[=SDKDIR]
                          create a universal binary build. SDKDIR specifies
                          which macOS SDK should be used to perform the build,
                          see Mac/README.rst. (default is no)
  --enable-framework[=INSTALLDIR]
                          create a Python.framework rather than a traditional
                          Unix install. optional INSTALLDIR specifies the
                          installation path. see Mac/README.rst (default is
                          no)
  --enable-shared         enable building a shared Python library (default is
                          no)
  --enable-profiling      enable C-level code profiling with gprof (default is
                          no)
  --enable-optimizations  enable expensive, stable optimizations (PGO, etc.)
                          (default is no)
  --enable-loadable-sqlite-extensions
                          support loadable extensions in _sqlite module, see
                          Doc/library/sqlite3.rst (default is no)
  --enable-ipv6           enable ipv6 (with ipv4) support, see
                          Doc/library/socket.rst (default is yes if supported)
  --enable-big-digits[=15|30]
                          use big digits (30 or 15 bits) for Python longs
                          (default is no)]

 Optional Packages:
  --with-PACKAGE[=ARG]    use PACKAGE [ARG=yes]
  --without-PACKAGE       do not use PACKAGE (same as --with-PACKAGE=no)
  --with-universal-archs=ARCH
                          specify the kind of universal binary that should be
                          created. this option is only valid when
                          --enable-universalsdk is set; options are:
                          ("32-bit", "64-bit", "3-way", "intel", "intel-32",
                          "intel-64", or "all") see Mac/README.rst
  --with-framework-name=FRAMEWORK
                          specify the name for the python framework on macOS
                          only valid when --enable-framework is set. see
                          Mac/README.rst (default is 'Python')
  --with-cxx-main[=COMPILER]
                          compile main() and link Python executable with C++
                          compiler specified in COMPILER (default is $CXX)
  --with-suffix=SUFFIX    set executable suffix to SUFFIX (default is '.exe')
  --with-pydebug          build with Py_DEBUG defined (default is no)
  --with-trace-refs       enable tracing references for debugging purpose
                          (default is no)
  --with-assertions       build with C assertions enabled (default is no)
  --with-lto              enable Link-Time-Optimization in any build (default
                          is no)
  --with-hash-algorithm=[fnv|siphash24]
                          select hash algorithm for use in Python/pyhash.c
                          (default is SipHash24)
  --with-address-sanitizer
                          enable AddressSanitizer memory allocation
                          controller, 'asan' (default is no)
  --with-memory-sanitizer enable MemorySanitizer memory allocation controller,
                          'msan' (default is no)
  --with-undefined-behavior-sanitizer
                          enable UndefinedBehaviorSanitizer memory allocation
                          controller, 'ubsan' (default is no)
  --with-libs='lib1 ...'  link against additional libs (default is no)
  --with-system-expat     build pyexpat module using an installed system expat
                          library, see Doc/library/pyexpat.rst (default is no)
  --with-system-ffi       build _ctypes module using an installed ffi library,
                          see Doc/library/ctypes.rst (default is system
                          dependant)
  --with-system-libmpdec  build _decimal module using an installed libmpdec
                          library, see Doc/library/decimal.rst (default is no)
  --with-tcltk-includes='-I...'
                          override search for Tcl and Tk include files
  --with-tcltk-libs='-L...'
                          override search for Tcl and Tk libs
  --with-dbmliborder=db1:db2:...
                          override order to check db backends for dbm. valid
                          value is a colon separated string with the backend
                          names `ndbm', `gdbm' and `bdb'.
  --with-doc-strings      enable documentation strings (default is yes)
  --with-pymalloc         enable specialized mallocs (default is yes)
  --with-c-locale-coercion
                          enable C locale coercion to a UTF-8 based locale
                          (default is yes)
  --with-valgrind         enable Valgrind support (default is no)
  --with-dtrace           enable DTrace support (default is no)
  --with-libm=STRING      override libm math library to STRING (default is
                          system dependant)
  --with-libc=STRING      override libc C library to STRING (default is system
                          dependant)
  --with-computed-gotos   enable computed gotos in evaluation loop (enabled by
                          default on supported compilers)
  --with-ensurepip[=install|upgrade|no]
                          "install" or "upgrade" using bundled pip (default is
                          upgrade)
  --with-openssl=DIR      override root of the OpenSSL directory to DIR
  --with-ssl-default-suites=[python|openssl|STRING]
                          override default cipher suites string, python: use
                          Python's preferred selection (default), openssl:
                          leave OpenSSL's defaults untouched, STRING: use a
                          custom string, PROTOCOL_SSLv2 ignores the setting,
                          see Doc/library/ssl.rst

https://bugs.python.org/issue39160