These changes make shared library support work again on 386 COFF
systems.
* coffcode.h (styp_to_sec_flags): Set SEC_SHARED_LIBRARY for a
STYP_NOLOAD | STYP_BSS section. Don't set SEC_NEVER_LOAD for a
STYP_INFO section.
(coff_compute_section_file_positions): Force vma and lma of _LIB
section to be zero.
(coff_set_section_contents): Count number of entries in new lma
field, not in vma.
* coffgen.c (make_a_section_from_file): Force lineno_count of
SEC_SHARED_LIBRARY section to be zero, since it is non-zero on the
SCO 3.2v4 shared library.
* seclet.c (rel): Copy over any section with contents, not just
loadable sections.
* coff-mips.c (ecoff_make_empty_symbol): Zero out newly allocated
symbol.