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Declare variable arguments

     #include <varargs.h>
To use the `varargs.h' version of variable argument lists, you must
declare your function with a call to the macro `va_alist' as its
argument list, and use `va_dcl' as the declaration.  _Do not use a
semicolon after `va_dcl'._
These macros cannot be used in a context where a return is syntactically
VA_ALIST and VA_DCL were the most widespread method of declaring
variable argument lists prior to ANSI C.