cmake HAVE_DECL_OPTARG examples

InsightSoftwareConsortium/ITK Modules/ThirdParty/TIFF/src/itktiff/cmake/SymbolChecks.cmake :32 

check_symbol_exists(optarg "getopt.h" HAVE_DECL_OPTARG)

Kitware/VTK ThirdParty/tiff/vtktiff/cmake/SymbolChecks.cmake :32 

check_symbol_exists(optarg "getopt.h" HAVE_DECL_OPTARG)

Ravbug/UnityHubNative wxWidgets/src/tiff/cmake/SymbolChecks.cmake :32 

check_symbol_exists(optarg "getopt.h" HAVE_DECL_OPTARG)