//     of the symbol gets the same global index as the first appearance.
type Loader struct {
	objs        []*oReader
	extStart    Sym   // from this index on, the symbols are externally defined
	builtinSyms []Sym // global index of builtin symbols

	objSyms []objSym // global index mapping to local index

	symsByName    [2]map[string]Sym // map symbol name to index, two maps are for ABI0 and ABIInternal