Go Up to Error and Warning Messages (Delphi)
Identifier
The identifier for the $WARN directive: SYMBOL_LIBRARY
Description
The symbol is tagged (using the library hint directive) as one that may not be available in all libraries. If you are likely to use different libraries, it may cause a problem.
The $WARN SYMBOL_LIBRARY ON/OFF compiler directive turns on or off all warnings about the library directive on symbols in the current unit.