[binutils-gdb] Avoid non-C++-enabled babeltrace versions

[Andreas Arnez <arnez at sourceware dot org>]

https://sourceware.org/git/gitweb.cgi?p=binutils-gdb.git;h=2d681be471cf8aff8f296cb7713c39e9aa4fc2bb

commit 2d681be471cf8aff8f296cb7713c39e9aa4fc2bb
Author: Andreas Arnez <arnez@linux.vnet.ibm.com>
Date:   Wed Apr 27 15:52:16 2016 +0200

    Avoid non-C++-enabled babeltrace versions
    
    In some babeltrace versions before 1.2.0, the header file iterator.h
    declares the enum values `BT_SEEK_*' within the struct declaration of
    bt_iter_pos.  The enum values are supposed to be globally-scoped, which
    works for C, but not for C++.  Later babeltrace versions declare the
    enum outside the struct:
    
      https://lists.lttng.org/pipermail/lttng-dev/2013-September/021411.html
    
    Now that GDB is compiled with C++, the GDB build fails on a system with
    an affected babeltrace version: the compiler complains about a missing
    declaration of BT_SEEK_BEGIN in ctf.c.
    
    This patch enhances the configure check to recognize such babeltrace
    versions as unusable for GDB.
    
    gdb/ChangeLog:
    
    	* configure.ac: Enhance configure check for babeltrace to reject
    	non-C++-enabled versions.
    	* configure: Regenerate.

Diff:
---
 gdb/ChangeLog    | 6 ++++++
 gdb/configure    | 1 +
 gdb/configure.ac | 1 +
 3 files changed, 8 insertions(+)

diff --git a/gdb/ChangeLog b/gdb/ChangeLog
index 1335563..df10de4 100644
--- a/gdb/ChangeLog
+++ b/gdb/ChangeLog
@@ -1,3 +1,9 @@
+2016-04-27  Andreas Arnez  <arnez@linux.vnet.ibm.com>
+
+	* configure.ac: Enhance configure check for babeltrace to reject
+	non-C++-enabled versions.
+	* configure: Regenerate.
+
 2016-04-26  Sanimir Agovic  <sanimir.agovic@intel.com>
 	    Keven Boell  <keven.boell@intel.com>
 	    Bernhard Heckel  <bernhard.heckel@intel.com>
diff --git a/gdb/configure b/gdb/configure
index 3cf95e7..228cb99 100755
--- a/gdb/configure
+++ b/gdb/configure
@@ -16390,6 +16390,7 @@ struct bt_iter_pos *pos = bt_iter_get_pos (bt_ctf_get_iter (NULL));
 			struct bt_ctf_event *event = NULL;
 			const struct bt_definition *scope;
 
+			pos.type = BT_SEEK_BEGIN;
 			bt_iter_set_pos (bt_ctf_get_iter (NULL), pos);
 			scope = bt_ctf_get_top_level_scope (event,
 			      				   BT_STREAM_EVENT_HEADER);
diff --git a/gdb/configure.ac b/gdb/configure.ac
index 70452d3..3aa132a 100644
--- a/gdb/configure.ac
+++ b/gdb/configure.ac
@@ -2286,6 +2286,7 @@ else
 			struct bt_ctf_event *event = NULL;
 			const struct bt_definition *scope;
 
+			pos.type = BT_SEEK_BEGIN;
 			bt_iter_set_pos (bt_ctf_get_iter (NULL), pos);
 			scope = bt_ctf_get_top_level_scope (event,
 			      				   BT_STREAM_EVENT_HEADER);