PR22245, Fix potential UB in bfd_set_error

[Alan Modra]

From: "Pavel I. Kryukov" <kryukov@frtk.ru>
Applied, thanks!

Passing enum as a first argument to variadic argument function
may lead to undefined behavior. The explanation on CERT site:
https://www.securecoding.cert.org/confluence/display/cplusplus/
EXP58-CPP.+Pass+an+object+of+the+correct+type+to+va_start

The bug was found by Kirill Nedostoev (nedostoev.ka@phystech.edu)
when he tried to build GNU binutils with Clang 7.

	PR 22245
	* bfd.c (bfd_set_error): Avoid UB on passing arg to va_start that
	undergoes default promotion.
	* bfd-in2.h: Regenerate.

diff --git a/bfd/ChangeLog b/bfd/ChangeLog
index 9ef407c..ce948c8 100644
--- a/bfd/ChangeLog
+++ b/bfd/ChangeLog
@@ -1,3 +1,10 @@
+2017-10-04  Pavel I. Kryukov <kryukov@frtk.ru>
+
+	PR 22245
+	* bfd.c (bfd_set_error): Avoid UB on passing arg to va_start that
+	undergoes default promotion.
+	* bfd-in2.h: Regenerate.
+
 2017-10-02  Alan Modra  <amodra@gmail.com>
 
 	* elf32-ppc.c (ppc_elf_relocate_section): Fix comment typo.
diff --git a/bfd/bfd-in2.h b/bfd/bfd-in2.h
index d126aed..62be566 100644
--- a/bfd/bfd-in2.h
+++ b/bfd/bfd-in2.h
@@ -7054,7 +7054,7 @@ bfd_error_type;
 
 bfd_error_type bfd_get_error (void);
 
-void bfd_set_error (bfd_error_type error_tag, ...);
+void bfd_set_error (int error_tag, ...);
 
 const char *bfd_errmsg (bfd_error_type error_tag);
 
diff --git a/bfd/bfd.c b/bfd/bfd.c
index 665f182..5da1a6f 100644
--- a/bfd/bfd.c
+++ b/bfd/bfd.c
@@ -497,7 +497,7 @@ FUNCTION
 	bfd_set_error
 
 SYNOPSIS
-	void bfd_set_error (bfd_error_type error_tag, ...);
+	void bfd_set_error (int error_tag, ...);
 
 DESCRIPTION
 	Set the BFD error condition to be @var{error_tag}.
@@ -507,7 +507,7 @@ DESCRIPTION
 */
 
 void
-bfd_set_error (bfd_error_type error_tag, ...)
+bfd_set_error (int error_tag, ...)
 {
   bfd_error = error_tag;
   if (error_tag == bfd_error_on_input)

-- 
Alan Modra
Australia Development Lab, IBM