Symbol 'SysTick_IRQn' could not be resolved
Seems like the solution with keeping “Generate under root” in place found.
My current project uses L151CCT , but definitely it should work with any other.
So, in my directory ../Drivers/CMSIS/Device/ST/STM32L1xx/Include
only three working files left:
stm32l1xx.h
stm32l151xc.h
system_stm32l1xx.h
All the other headers I moved to archive just in case.
Actually it’s been said above about deleting all the other headers from this directory. I’m not so radical 
Definitely this is a bug (not huge, but...), that should be fixed in the next releases.
Happy STMting