Cray: CMAKE_${lang}_IMPLICIT_INCLUDE_DIRECTORIES is not populated
CrayPrgEnv.cmake:__cray_extract_implicit
uses ${CMAKE_${lang}_COMPILER} ${CMAKE_${lang}_VERBOSE_FLAG} -o ${BIN}
to invoke the compiler driver. When a source file is not provided the driver does not invoke the compiler and thus the include options are not scraped.
It's possible this used to work with craype 1.x? We are using craype 2.2.1 currently. Adding a source file fixed the issue (tested gnu,cray, and intel PrgEnvs).