Properly merge hidden versioned symbol

Properly merge hidden versioned symbol

The hidden versioned symbol can only be merged with the versioned
symbol with the same symbol version.  _bfd_elf_merge_symbol should
check the symbol version before merging the new hidden versioned
symbol with the existing symbol.  _bfd_elf_link_hash_copy_indirect can't
copy any references to the hidden versioned symbol.   We need to
bind a symbol locally when linking executable if it is locally defined,
hidden versioned, not referenced by shared library and not exported.

bfd/

	PR ld/18720
	* elflink.c (_bfd_elf_merge_symbol): Add a parameter to indicate
	if the new symbol matches the existing one.  The new hidden
	versioned symbol matches the existing symbol if they have the
	same symbol version. Update the existing symbol only if they
	match.
	(_bfd_elf_add_default_symbol): Update call to
	_bfd_elf_merge_symbol.
	(_bfd_elf_link_assign_sym_version): Don't set the hidden field
	here.
	(elf_link_add_object_symbols): Override a definition only if the
	new symbol matches the existing one.
	(_bfd_elf_link_hash_copy_indirect): Don't copy any references to
	the hidden versioned symbol.
	(elf_link_output_extsym): Bind a symbol locally when linking
	executable if it is locally defined, hidden versioned, not
	referenced by shared library and not exported.  Turn on
	VERSYM_HIDDEN only if the hidden vesioned symbol is defined
	locally.

ld/testsuite/

	PR ld/18720
	* ld-elf/indirect.exp: Run tests for PR ld/18720.
	* ld-elf/pr18720.out: New file.
	* ld-elf/pr18720a.c: Likewise.
	* ld-elf/pr18720b.c: Likewise.
	* ld-elf/pr18720c.c: Likewise.