* ldmain.c (main): Initialise print_gc_sections field of link_info structure.

* lexsup.c: Add --print-gc-sections and --no-print-gc-sections switches.
* ld.texinfo: Document new switches.
* NEWS: Mention new switches.
* bfdlink.h (struct bfd_link_info): New field: print_gc_sections.
* elflink.c (elf_gc_sweep): If info.print_gc_sections is true, list removed sections to stderr.