External Declarations The external directive, which replaces the block in a procedure or function declaration, allows you to call routines
that are compiled separately from your program. External routines can come from object files or dynamically loadable
libraries.
When importing a C function that takes a variable number of parameters, use the varargs directive. For example,
function printf(Format: PChar): Integer; cdecl; varargs;
The varargs directive works only with external routines and only with the cdecl calling convention.
