jerryscript: Board NRF52_DK: failure with make retarget.cpp:(.text.__wrap_main+0xa): undefined reference to `main'

Using os ubuntu/xenial64, the make BOARD=NRF52_DK failed with:

Compile [100.0%]: launcher.cpp
Link: mbedos5
./BUILD/NRF52_DK/GCC_ARM/mbed-os/platform/retarget.o: In function `__wrap_main':
retarget.cpp:(.text.__wrap_main+0xa): undefined reference to `main'
collect2: error: ld returned 1 exit status
[ERROR] ./BUILD/NRF52_DK/GCC_ARM/mbed-os/platform/retarget.o: In function `__wrap_main':
retarget.cpp:(.text.__wrap_main+0xa): undefined reference to `main'
collect2: error: ld returned 1 exit status

[mbed] ERROR: "python" returned error code 1.
[mbed] ERROR: Command "python -u /home/ubuntu/jerryscript/targets/mbedos5/mbed-os/tools/make.py -t GCC_ARM -m NRF52_DK --source . --source ../../ --build ./BUILD/NRF52_DK/GCC_ARM -j0 -D CONFIG_MEM_HEAP_AREA_SIZE=(1024*16)" in "/home/ubuntu/jerryscript/targets/mbedos5"
---
Makefile:56: recipe for target 'all' failed
make: *** [all] Error 1

Complet make: jerry.txt

It would be interesting to know which ubuntu is usually sucessfull/accepted with compilation to remove as many unknowns as possible.

Basic preparation and make : have I forgotten something?

      sudo apt-get -y update \
      && sudo apt-get -y upgrade \
      && sudo apt-get -y install \
        cmake gcc-arm-none-eabi python-pip
      
      sudo -H pip install --upgrade pip \
      && sudo -H pip install -U mbed-cli \
      && git clone https://github.com/jerryscript-project/jerryscript.git \
      && cd jerryscript/targets/mbedos5 \
      && sudo pip -H install -r tools/requirements.txt \
      && make getlibs \
      && make BOARD=NRF52_DK