Failed build of led_ws2812 in ncs v1.5.0

Question

The error is 
 CMake Error at ../../../cmake/extensions.cmake:416 (add_library): 
 No SOURCES given to target: drivers__spi 
 This similar to 
 https://devzone.nordicsemi.com/f/nordic-q-a/72810/custom-board-build-fails-with-sdk-1-5-0-works-with-1-4-0/299782#299782 
 BUT 
 It builds OK when building for nrf9160-dk but not when building for actinius_icarus_som 
 Other builds for actinius_icarus_som work OK. I guess this is SPI-related? 
 Any suggestions pls?

paul_tanner · Accepted Answer

I think the problem is specific to the SOM. When I had built this with ncs v1.4 I did not specify the miso and sck pins. In 1.5 you can do this. Initially I made a bad choice of pins 28 and 29 which are internally connected, therefore not spare. Changing to a couple of other pins fixed the problem. 
 I'm still working with another issue when I add this device into an application that uses other SPIs. I'll report that separately unless I solve it.