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.