coff patch for ld -r -S crash with djgpp

[Mark E.]

BTW, the bug involves -r and -S, _bfd_coff_final_link and mark_relocs in cofflink.c. _bfd_coff_final_link  
determines how much space to allocate for holding information about relocs, etc. by examining the 
output bfd. Then mark_relocs crawls through the input bfds and reads in the relocs and marks them 
used. The input bfds still contain those sections excluded from the output, so a memory overflow can 
occur if these extra relocs aren't excluded.

Mark