toolchain: Bump ARC tools to arc-2016.09-rc1

As described at:
4520524ba0
this commit continues a series of updates of ARC tools.
This time we're updating tools to arc-2016.09-rc1.

This update contains a lot of important fixes, e.g. it fixes:
http://autobuild.buildroot.net/results/4c7/4c77f33c842b37bf28cb931edf1b290e1bf4d93c//
http://autobuild.buildroot.net/results/902/902729a0b98675ad803939e3ecdcf230065a6012//
and other failures.

Other important change is that we also update gdb. Now we are
using gdb 7.12.

This version of gdb requires C++ toolchain support so we add
corresponding dependency to gdb Config.in file.

Signed-off-by: Vlad Zakharov <vzakhar@synopsys.com>
[Thomas:
 - fix dependency on C++ of gdb, it must use BR2_INSTALL_LIBSTDCPP
 - add comment about the C++ dependency of gdb on ARC.]
Signed-off-by: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>

package/binutils/Config.in.host

@@ -22,7 +22,7 @@ endchoice
 
 config BR2_BINUTILS_VERSION
 	string
-	default "arc-2016.09-eng015"	if BR2_arc
+	default "arc-2016.09-rc1"	if BR2_arc
 	default "2.25.1"	if BR2_BINUTILS_VERSION_2_25_X
 	default "2.26.1"	if BR2_BINUTILS_VERSION_2_26_X
 	default "2.27"		if BR2_BINUTILS_VERSION_2_27_X

package/binutils/binutils.hash

@@ -5,4 +5,4 @@ sha512  9d9165609fd3b0f20d616f9891fc8e2b466eb13e2bfce40125e12427f8f201d20e2b8322
 sha512	cf276f84935312361a2ca077e04d0b469d23a3aed979d8ba5d92ea590904ffb2c2e7ed12cc842822bfc402836be86f479660cef3791aa62f3753d8a1a6f564cb  binutils-2.27.tar.bz2
 
 # Locally calculated (fetched from Github)
-sha512  f8cc7529fbe3cb52b666b92e1353063a8a36ea07fa8c5aa8359252f4222feaed15253b6a137033c74dabc0ae784daf8a7978e69ebdb8bf8cd6b8bb61c84bf181  binutils-arc-2016.09-eng015.tar.gz
+sha512  d0befdeb0a7b76efd1ad655fc062cde2aa67be7b26210c913ab2709e069d815c4ff2863ce7add1f6434da5a2f4faf1ce5a5bc3d0e64f3e04548a7479f24edcbc  binutils-arc-2016.09-rc1.tar.gz

package/binutils/binutils.mk

@@ -9,7 +9,7 @@
 BINUTILS_VERSION = $(call qstrip,$(BR2_BINUTILS_VERSION))
 ifeq ($(BINUTILS_VERSION),)
 ifeq ($(BR2_arc),y)
-BINUTILS_VERSION = arc-2016.09-eng015
+BINUTILS_VERSION = arc-2016.09-rc1
 else
 BINUTILS_VERSION = 2.25.1
 endif