newlib: fix newlib host/target workaround

  # newlib expects CC to build for build platform, not host platform

  preConfigure = ''

    export CC=cc

  '' +

  # newlib tries to disable itself when building for Linux *except*

  # when native-compiling.  Unfortunately the check for "is cross

  # compiling" was written when newlib was part of GCC and newlib

  # was built along with GCC (therefore newlib was built to execute

  # on the targetPlatform, not the hostPlatform).  Unfortunately

  # when newlib was extracted from GCC, this "is cross compiling"

  # logic was not fixed.  So we must disable it.

  ''

    substituteInPlace configure --replace 'noconfigdirs target-newlib target-libgloss' 'noconfigdirs'

  '';

  configurePlatforms = [ "build" "target" ];

  # flags copied from https://community.arm.com/support-forums/f/compilers-and-libraries-forum/53310/gcc-arm-none-eabi-what-were-the-newlib-compilation-options

  # sort alphabetically

  configureFlags = [

    "--with-newlib"

    "--host=${stdenv.buildPlatform.config}"

    # The newlib configury uses `host` to refer to the platform

    # which is being used to compile newlib.  Ugh.  It does this

    # because of its history: newlib used to be distributed with and

    # built as part of gcc.

    #

    # To prevent nixpkgs from going insane, this package presents the

    # "normal" view to the outside world: the binaries in $out will

    # execute on `stdenv.hostPlatform`.  We then fool newlib's build

    # process into doing the right thing.

    "--host=${stdenv.targetPlatform.config}"

  ] ++ (if !nanoizeNewlib then [

    "--disable-newlib-supplied-syscalls"

    "--disable-nls"