(b_out_get_reloc_upper_bound): For BSS section, just return 0.

(b_out_get_reloc_upper_bound): For BSS section, just return 0.
(aligncode): When shrinking, the addend should be set to the current offset in
the section plus the number of bytes of padding that will actually be retained.
(b_out_relax_section): If a section contains no relocations, don't bother
processing them.
(b_out_get_relocated_section_contents): Set reloc_done.  Assert that
bfd_get_section_contents returns true.  Check that relocs are properly ordered.
(b_out_get_relocated_section_contents, case ALIGNDONE): Assert that reloc's
addend falls between the current source offset and the raw size of the input
section.

Changed some indentation, deleted trailing whitespace, fixed some comments,
removed some "#if 1" lines.
(output_addr): New macro.
(calljx_callback, callj_callback, get_value, abs32code, aligncode,
b_out_get_relocated_section_contents): Use it for readability.