PR binutils/3874

PR binutils/3874
* elf32-avr.c (avr_link_hash_table): Check to make sure that the hash table was created by elf32_avr_link_hash_table_create before using it.
  (elf32_avr_link_hash_newfunc): New function.  Just pass the call through to _bfd_elf_link_hash_newfunc.
  (elf32_avr_link_hash_table_create): Use elf32_avr_link_hash_newfunc instead of _bfd_elf_link_hash_newfunc.
  (elf32_avr_relocate_section): Check for the hash table pointer being NULL.
  (elf32_avr_relax_section, avr_build_one_stub, elf32_avr_setup_params, get_local_syms, elf32_avr_size_stubs, elf32_avr_build_stubs): Likewise.