Plugin target handling

This patch fixes failures with LTO on mingw32 targets.  Since git
commit 7cf7fcc83c all possible targets (minus binary) are matched in
bfd_check_format_matches rather than lower priority targets being
excluded once a higher priority target matches.  During linking that
results in the ld/plugin.c plugin_object_p function being called with
the input file xvec set to plugin_vec, which means
plugin_get_ir_dummy_bfd doesn't see the real format of the file
(pe-i386).  It defaults to the output format instead, which happens to
be pei-i386, and this wrong choice persists for the dummy bfd.
pei-i386 isn't recognised as a valid linker input file.

So, omit recognizing a plugin object in bfd_check_format_matches when
some other object format matches, and make sure those other object
formats are checked first.

	* format.c (bfd_check_format_matches): Don't match plugin target
	if another target matches.  Expand comment.
	* targets.c (_bfd_target_vector): Move plugin_vec after all other
	non-corefile targets, outside !SELECT_VECS.
	* config.bfd: Don't handle targ=plugin here.
	* configure.ac: Don't add plugin to enable_targets or handle in
	target loop setting selvecs and other target vars.
	* configure: Regenerate.

1 files changed, 8 insertions, 1 deletions

diff --git a/bfd/format.c b/bfd/format.c
index 97a9229..1d1363d 100644
--- a/bfd/format.c
+++ b/bfd/format.c
@@ -290,8 +290,15 @@ bfd_check_format_matches (bfd *abfd, bfd_format format, char ***matching)
     {
       const bfd_target *temp;
 
-      /* Don't check the default target twice.  */
+      /* The binary target matches anything, so don't return it when
+	 searching.  Don't match the plugin target if we have another
+	 alternative since we want to properly set the input format
+	 before allowing a plugin to claim the file.  Also, don't
+	 check the default target twice.  */
       if (*target == &binary_vec
+#if BFD_SUPPORTS_PLUGINS
+	  || (match_count != 0 && *target == &plugin_vec)
+#endif
 	  || (!abfd->target_defaulted && *target == save_targ))
 	continue;