* elf32-s390: Major rework that introduces all recent changes to

* elf32-s390: Major rework that introduces all recent changes to
the s390 backends.  Get a closer match to elf32-i386.
(elf_s390_relocate_section): Make use of dynamic section short-cuts.
Localise vars, and delay setting.  Better error reporting, replace
BFD_ASSERT with abort.  Check ELF_LINK_HASH_DEF_DYNAMIC to see if a
symbol is not defined in the regular object file and tread the weak
definition as the normal one.  Don't discard relocs for undefweak or
undefined symbols and check !DEF_REGULAR as well as DEF_DYNAMIC in
test for avoided copy relocs.  Reinstate fudge for unresolved relocs
in debugging sections.
(elf32_s390_adjust_dynamic_symbol): Handle nocopyreloc.  Don't do copy
reloc processing for weakdefs.  Remove redundant casts and aborts.
Delay setting of vars until needed.  Move creation of dynamic symbols
and allocation of .plt and .rela.plt to allocate_dynrelocs.  Replace
BFD_ASSERT with abort.  Discard .plt entries for everything with
plt.refcount <= 0.
(elf_s390_check_relocs):  Don't allocate space for dynamic relocs,
.got or .relgot here but do it in allocate_dynrelocs.  Reference count
possible .plt and .got entries.  Don't test input section SEC_READONLY
here to try to avoid copy relocs, and keep dyn_relocs regardless of
ELF_LINK_NON_GOT_REF.  Don't set DF_TEXTREL here.  Delay setting of
variables until needed.  Remove separate switch stmt for creating .got
section.  Initialise local_got_refcounts to 0.  Cache pointer to
"sreloc" section in elf_section_data. Tweak condition under which .got
created.  Report files with bad relocation section names.
(elf_s390_finish_dynamic_symbol): Don't copy relocs for symbols that
have been forced local.  Use same test to decide if we can use a
relative reloc for got as elf_s390_relocate_section.  Expand SHN_UNDEF
comment.  Move expressions out of function calls.  Replace BFD_ASSERT
with abort.
(elf_s390_finish_dynamic_sections): Migrate common code out of switch
statement.  Replace BFD_ASSERT with abort.
(elf_s390_size_dynamic_sections): Call readonly_dynrelocs. Rename "i"
to "ibfd".  Allocate space for local dyn relocs.  Use DF_TEXTREL flag
instead of looking up section names for DT_TEXTREL.  Replace
BFD_ASSERT with abort.  Zero out the dynamic allocated content space.
Add a comment to remind us that one day this ought to be fixed.
(struct elf_s390_link_hash_entry): Rename "root" to "elf".
(struct elf_s390_link_hash_table): Likewise.
(elf_s390_link_hash_newfunc): Rename to link_hash_newfunc and get
rid of unnecessary casts.
(struct elf_s390_dyn_relocs): Add "sec", and "pc_count" fields.
Remove "section" field.
(elf_s390_gc_sweep_hook): Sweep dyn_relocs and local_dynrel.
Reference count possible .plt entries.  Don't deallocate .got and
.relgot space here.
(struct elf_s390_pcrel_relocs_copied): Rename to elf_s390_dyn_relocs.
Update comment.
(struct elf_s390_link_hash_entry): Rename pcrel_relocs_copied to
dyn_relocs.
(elf_s390_discard_copies):  Delete.
(elf_s390_link_hash_traverse): Delete.
(bfd_elf32_bfd_final_link): Delete.  (ie. use regular final link
rather than gc variety).
(struct elf_s390_link_hash_table): Add sgot, sgotplt, srelgot, splt,
srelplt, sdynbss, srelbss fields.
(elf_s390_link_hash_table_create): Init them.
(WILL_CALL_FINISH_DYNAMIC_SYMBOL): Define.
(allocate_dynrelocs): New function.
(create_got_section): New function.
(elf_backend_can_refcount): Define.
(elf_backend_copy_indirect_symbol): Define.
(elf_s390_copy_indirect_symbol): New function.
(elf_s390_create_dynamic_sections): New function.
(readonly_dynrelocs): New function.
* elf64-s390x: Likewise.