Support %Lx, %Lu, %Ld in _bfd_error_handler format

One way to print 64-bit bfd_vma or bfd_size_type values on 32-bit
hosts is to cast the value to long long and use the 'll' modifier in
printf format strings.  However, that's awkward because we also
support the Microsoft C library printf that uses 'I64' as a modifier
instead, and having variants of translated strings would not endear us
to the translation project.  So, rewrite the 'll' modifier in
_doprint for Microsoft.  Even with that capability it's not so nice
for 32-bit code to need casts to long long, so this patch makes 'L' a
modifier for bfd_vma rather than an alias for 'll'.

I've then used the new 'L' modifier to fix selected format strings.

	* bfd.c (_doprnt): Rewrite "ll" and "L" modifiers to "I64" for
	__MSVCRT__.  Support "L" modifier for bfd_vma.  Formatting.
	* elf.c (setup_group): Use "Lx" to print sh_size.
	(_bfd_elf_setup_sections): Remove unnecessary cast and print
	unknown section type in hex.
	(copy_special_section_fields): Style fix.
	(bfd_section_from_shdr): Correct format for sh_link.  Use a
	common error message for all the variants of unrecognized
	section types.
	(assign_file_positions_for_load_sections): Use "Lx" for lma
	adjust error message.
	(assign_file_positions_for_non_load_sections): Formatting.
	(rewrite_elf_program_header): Formatting.  Use "Lx" for
	bfd_vma values in error messages.
	* elfcode.h (elf_slurp_reloc_table_from_section): Cast
	ELF_R_SYM value to type expected by format.
	* elflink.c (elf_link_read_relocs_from_section): Use "Lx"
	in error messages.
	(elf_link_add_object_symbols): Use "Lu" for symbol sizes.
	(elf_link_input_bfd): Use "Lx" for r_info.
	(bfd_elf_gc_record_vtinherit): Use "Lx" for offset.

bfd/elfcode.h

@@ -1446,7 +1446,7 @@ elf_slurp_reloc_table_from_section (bfd *abfd,
 	  _bfd_error_handler
 	    /* xgettext:c-format */
 	    (_("%B(%A): relocation %d has invalid symbol index %ld"),
-	     abfd, asect, i, ELF_R_SYM (rela.r_info));
+	     abfd, asect, i, (long) ELF_R_SYM (rela.r_info));
 	  relent->sym_ptr_ptr = bfd_abs_section_ptr->symbol_ptr_ptr;
 	}
       else