[newlib-cygwin] Cygwin: Update ELF target used by dumper on x86_64

[Jon TURNEY]

https://sourceware.org/git/gitweb.cgi?p=newlib-cygwin.git;h=38f88601469f4a6ab7cf42e1f076775c99eb17f2

commit 38f88601469f4a6ab7cf42e1f076775c99eb17f2
Author: Jon Turney <jon.turney@dronecode.org.uk>
Date:   Mon Jun 29 14:36:00 2020 +0100

    Cygwin: Update ELF target used by dumper on x86_64
    
    Like [1], but actually making the effort to be 'usable' and 'tested'.
    
    [1] https://cygwin.com/pipermail/cygwin/2019-October/242815.html

Diff:
---
 winsup/utils/dumper.cc | 10 ++++++++--
 1 file changed, 8 insertions(+), 2 deletions(-)

diff --git a/winsup/utils/dumper.cc b/winsup/utils/dumper.cc
index 226c2283d..e16d80a36 100644
--- a/winsup/utils/dumper.cc
+++ b/winsup/utils/dumper.cc
@@ -645,7 +645,13 @@ dumper::init_core_dump ()
 {
   bfd_init ();
 
-  core_bfd = bfd_openw (file_name, "elf32-i386");
+#ifdef __x86_64__
+  const char *target = "elf64-x86-64";
+#else
+  const char *target = "elf32-i386";
+#endif
+
+  core_bfd = bfd_openw (file_name, target);
   if (core_bfd == NULL)
     {
       bfd_perror ("opening bfd");
@@ -658,7 +664,7 @@ dumper::init_core_dump ()
       goto failed;
     }
 
-  if (!bfd_set_arch_mach (core_bfd, bfd_arch_i386, 0))
+  if (!bfd_set_arch_mach (core_bfd, bfd_arch_i386, 0 /* = default */))
     {
       bfd_perror ("setting bfd architecture");
       goto failed;