cmake COVISE_HAS_PREPROCESSOR_ENTRY examples

hlrs-vis/covise cmake/CoviseHelperMacros.cmake :241 

MACRO(COVISE_HAS_PREPROCESSOR_ENTRY CONTENTS KEYWORD VARIABLE)

hlrs-vis/covise cmake/CoviseHelperMacros.cmake :250 

ENDMACRO(COVISE_HAS_PREPROCESSOR_ENTRY)