build (master) $ ninja

[0/1] Re-running CMake...

CMake Warning at /Users/manurao/temp/zephyr/cmake/app/boilerplate.cmake:167 (message):

  The build directory must be cleaned pristinely when changing boards

Call Stack (most recent call first):

  CMakeLists.txt:3 (include)

-- Selected BOARD nrf52_pca10040

Zephyr version: 1.13.99

Parsing Kconfig tree in /Users/manurao/temp/zephyr/Kconfig

Loading /Users/manurao/temp/zephyr/samples/hello_world/build/zephyr/.config as base

CMake Warning at /Users/manurao/temp/zephyr/cmake/toolchain.cmake:48 (message):

  gccarmemb is deprecated, please use gnuarmemb instead

Call Stack (most recent call first):

  /Users/manurao/temp/zephyr/cmake/app/boilerplate.cmake:269 (include)

  CMakeLists.txt:3 (include)

-- Generating zephyr/include/generated/generated_dts_board.h

-- Cache files will be written to: /Users/manurao/Library/Caches/zephyr

CMake Error at ../../CMakeLists.txt:544 (message):

  The Zephyr library 'drivers__i2c' was created without source files.  Empty

  (non-imported) libraries are not supported.  Either make sure that the

  library has the sources it should have, or make sure it is not created when

  it has no source files.

-- Configuring incomplete, errors occurred!

See also "/Users/manurao/temp/zephyr/samples/hello_world/build/CMakeFiles/CMakeOutput.log".

See also "/Users/manurao/temp/zephyr/samples/hello_world/build/CMakeFiles/CMakeError.log".

FAILED: build.ninja 

/usr/local/Cellar/cmake/3.11.0/bin/cmake -H/Users/manurao/temp/zephyr/samples/hello_world -B/Users/manurao/temp/zephyr/samples/hello_world/build

ninja: error: rebuilding 'build.ninja': subcommand failed

build (master) $