PATCH for ld on Cygwin: avoid core dump when linked-to DLL has no exports

[Eric Hanchrow]

This patch works around, or perhaps even fixes, a problem that I
recently had.  I was trying to link against a DLL that (by accident)
had no exports, like this:

        ld sans_exports.dll 

I was seeing a seg fault as the linker was attempting to read from
`expdata', even though that pointed to uninitialized memory.

I'm not certain that this is the best solution, but it seems
reasonable.  

    --- ./ChangeLog~        2003-03-07 18:50:18.000000000 -0800
    +++ ./ChangeLog 2003-04-30 10:00:02.000000000 -0700
    @@ -1,3 +1,8 @@
    +2003-04-30  Eric Hanchrow  <erich@votehere.net>
    +
    +       * pe-dll.c (pe_implied_import_dll): Don't crash when export_size
    +       is zero; instead print error and return FALSE.
    +
     2003-03-04  Dmitry Diky  <diwil@mail.ru>

            * Makefile.am: Add new devices x1122 x1132 emulation
    --- ./pe-dll.c~ 2003-02-28 22:00:15.000000000 -0800
    +++ ./pe-dll.c  2003-04-29 17:03:34.000000000 -0700
    @@ -2531,6 +2531,13 @@

       export_rva = pe_get32 (dll, opthdr_ofs + 96);
       export_size = pe_get32 (dll, opthdr_ofs + 100);
    +
    +  if (0 == export_size)
    +    {
    +      einfo ("%X%s: this DLL has no exports\n", filename);
    +      return FALSE;
    +    }
    +  
       nsections = pe_get16 (dll, pe_header_offset + 4 + 2);
       secptr = (pe_header_offset + 4 + 20 +
                pe_get16 (dll, pe_header_offset + 4 + 16));

-- 
But users will not now with glad cries glom on to a language that
gives them no more than what Scheme or Pascal gave them.

        -- Guy Steele, http://www.sun.com/research/jtech/pubs/98-oopsla-growing.ps