Failure to compile uclibc-ng abiv2 toolchain in Ubuntu Xenial chroot

[ioerror]

I attempted to build the toolchain using an Ubuntu Xenial chroot configured as follows:

sudo apt install -y debootstrap
debootstrap xenial xenial-chroot
sudo chroot xenial-chroot add-apt-repository universe
sudo chroot xenial-chroot apt update
sudo chroot xenial-chroot apt install -y build-essential wget unzip bc git
sudo chroot xenial-chroot apt install -y texinfo bison flex libgmp-dev libmpfr-dev libmpc-dev
sudo chroot xenial-chroot
# Inside Xenial chroot
git clone https://github.com/c-sky/toolchain-build
cd toolchain-build

Fetching the source is sucessful but the mklink target isn't valid:

./build-csky-gcc.py --abi=abiv2 --tos=linux --libc=uclibc-ng --init

====> toolchain components = ['binutils', 'gcc', 'linux-libc-headers', 'uclibc-ng', 'gdb', 'mklink']

<-- component 'binutils' source code url ['/root/toolchain-build/source//binutils'] is ok

<-- component 'gcc' source code url ['/root/toolchain-build/source//gcc'] is ok

<-- component 'linux-libc-headers' source code url ['/root/toolchain-build/source//linux-libc-headers'] is ok

<-- component 'uclibc-ng' source code url ['/root/toolchain-build/source//uclibc-ng'] is ok

<-- component 'gdb' source code url ['/root/toolchain-build/source//gdb'] is ok

<-- component 'mklink' source code url ['/root/toolchain-build/source//mklink'] is not valid

Building is sucessful with the following command until the uclibc-ng component:

./build-csky-gcc.py --abi=abiv2 --tos=linux --libc=uclibc-ng

The final component uclibc-ng fails to build with the following error:

====> start building component 'uclibc-ng' ... ...

--> multilib option: ('mlittle-endian', 'mcpu=ck810f', 'mfloat-abi=soft', 'mpic')
  MKDIR include/config
  MKDIR include/generated
  HOSTCC-o extra/config/conf.o
  GEN extra/config/zconf.tab.c
  GEN extra/config/zconf.lex.c
  GEN extra/config/zconf.hash.c
  HOSTCC-o extra/config/zconf.tab.o
  HOSTCC extra/config/conf
***
*** Can't find default configuration "extra/Configs/defconfigs/csky/ck810_le_defconfig"!
***
Makefile.in:509: recipe for target 'ck810_le_defconfig' failed

--> start error output

error code: 2
make: *** [ck810_le_defconfig] Error 1

<-- end error output

exec command: export PATH=/root/toolchain-build/install-csky-linux-uclibcabiv2-uclibc-ng/bin/:$PATH;make ARCH=csky ck810_le_defconfig