enable_language (Fortran)
include(CheckSourceRuns)
set(Fortran 1) # test that this is tolerated
check_source_runs(Fortran [=[
PROGRAM TEST_HAVE_PRINT
PRINT *, 'Hello'
END
]=] SHOULD_BUILD)
if(NOT SHOULD_BUILD)
message(SEND_ERROR "Test fail for valid Fortran source.")
endif()