Decorated symbols in import libs (BUG 30421)

  PR 30421
  * cofflink.c (_decoration_hash_newfunc): New function. (_bfd_coff_link_hash_table_init): Call it.
  * libcoff-in.h (struct coff_link_hash_table): Add decoration_hash field. (struct decoration_hash_entry): Declare. (_decoration_hash_newfunc): Prototype.
  * libcoff.h: Regenerate.

  * emultempl/pe.em (set_decoration): New function. (pe_fixup_stdcalls): Call the new function.
  * emultempl/pep.em (set_decoration): New function. (pep_fixup_stdcalls): Call the new function.
  * pe-dll.c (make_one): Check for decoated symbols.