gcc: allow the selection of upstream GCC 7.x for ARC

Upstream gcc now has support for ARC, as of 7.x, with 7.2 being
usable, so let's allow its selection.

GCC from Synopsys GitHub still has a lot of fixes and improvements
most of which will be a part of the next upstream release but let's
see how it goes and if we see vanilla GCC doesn't require way too many
back-ported patches we'll be able to get rid of Synopsys GitHub here
at all.

As of today the only really required back-port is the one for non-uClibc
libc.

Back-ported from upstream master with help of:
-------------------->8--------------------
git format-patch 927c0132251f -1 -- . ':!gcc/ChangeLog' ':!libgcc/ChangeLog'
-------------------->8--------------------

Signed-off-by: Alexey Brodkin <abrodkin@synopsys.com>
Cc: Arnout Vandecappelle (Essensium/Mind) <arnout@mind.be>
Cc: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>
Cc: Peter Korsgaard <peter@korsgaard.com>
Signed-off-by: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>

package/gcc/7.2.0/0893-ARC-Configure-script-to-allow-non-uclibc-based-tripl.patch

@@ -0,0 +1,51 @@
+From 927c0132251f1cd3452b96ebd75f1b06bc53e4ec Mon Sep 17 00:00:00 2001
+From: claziss <claziss@138bc75d-0d04-0410-961f-82ee72b054a4>
+Date: Mon, 10 Jul 2017 13:55:26 +0000
+Subject: [PATCH] [ARC] Configure script to allow non uclibc based triplets
+
+gcc/
+2017-07-10  Vineet Gupta <vgupta@synopsys.com>
+
+        * config.gcc: Remove uclibc from arc target spec.
+
+libgcc/
+2017-07-10  Vineet Gupta <vgupta@synopsys.com>
+
+        * config.host: Remove uclibc from arc target spec.
+
+git-svn-id: svn+ssh://gcc.gnu.org/svn/gcc/trunk@250097 138bc75d-0d04-0410-961f-82ee72b054a4
+Signed-off-by: Alexey Brodkin <abrodkin@synopsys.com>
+---
+ gcc/config.gcc     | 2 +-
+ libgcc/config.host | 2 +-
+ 2 files changed, 2 insertions(+), 2 deletions(-)
+
+diff --git a/gcc/config.gcc b/gcc/config.gcc
+index 1b47457..933a451 100644
+--- a/gcc/config.gcc
++++ b/gcc/config.gcc
+@@ -1044,7 +1044,7 @@ arc*-*-elf*)
+ 	big*)	tm_file="arc/big.h ${tm_file}"
+ 	esac
+ 	;;
+-arc*-*-linux-uclibc*)
++arc*-*-linux*)
+ 	tm_file="arc/arc-arch.h dbxelf.h elfos.h gnu-user.h linux.h linux-android.h glibc-stdint.h arc/linux.h ${tm_file}"
+ 	tmake_file="${tmake_file} arc/t-arc"
+ 	extra_gcc_objs="driver-arc.o"
+diff --git a/libgcc/config.host b/libgcc/config.host
+index 989ac71..a5ab453 100644
+--- a/libgcc/config.host
++++ b/libgcc/config.host
+@@ -383,7 +383,7 @@ arc*-*-elf*)
+ 	extra_parts="crti.o crtn.o crtend.o crtbegin.o crtendS.o crtbeginS.o"
+ 	extra_parts="$extra_parts crttls.o"
+ 	;;
+-arc*-*-linux-uclibc*)
++arc*-*-linux*)
+ 	tmake_file="${tmake_file} t-slibgcc-libgcc t-slibgcc-nolc-override arc/t-arc-uClibc arc/t-arc"
+ 	extra_parts="$extra_parts crti.o crtn.o"
+ 	extra_parts="$extra_parts crttls.o"
+-- 
+2.10.2
+

package/gcc/Config.in.host

@@ -58,7 +58,6 @@ config BR2_GCC_VERSION_6_X
 config BR2_GCC_VERSION_7_X
 	bool "gcc 7.x"
 	# Broken or unsupported architectures
-	depends on !BR2_arc
 	depends on !BR2_or1k
 	select BR2_TOOLCHAIN_GCC_AT_LEAST_7
 

package/gcc/gcc.mk

@@ -10,7 +10,7 @@
 
 GCC_VERSION = $(call qstrip,$(BR2_GCC_VERSION))
 
-ifeq ($(BR2_arc),y)
+ifeq ($(BR2_GCC_VERSION_ARC),y)
 GCC_SITE = $(call github,foss-for-synopsys-dwc-arc-processors,gcc,$(GCC_VERSION))
 GCC_SOURCE = gcc-$(GCC_VERSION).tar.gz
 else ifeq ($(BR2_or1k),y)