Unused dependencies can be determined using ldd(1). See the -u option.
Various ELF ABI extensions have been added. See Initialization and Termination Sections, Initialization and Termination Routines, Table 7–3, Table 7–8, Table 7–9, Group Section, Table 7–10, Table 7–20, Table 7–32, Table 7–33, and Program Loading (Processor-Specific).
Greater flexibility in the use of link-editor environment variables has been provided with the addition of _32 and _64 variants. See Environment Variables.