package/libs/gmp: update libgmp to 6.1.0

Update also the library version of gmp to 6.1.0.
Switch download to use the GNU alias.

Signed-off-by: Hannu Nyman <hannu.nyman@iki.fi>

SVN-Revision: 48712

package/libs/gmp/Makefile

@@ -1,5 +1,5 @@
 #
-# Copyright (C) 2006-2014 OpenWrt.org
+# Copyright (C) 2006-2016 OpenWrt.org
 #
 # This is free software, licensed under the GNU General Public License v2.
 # See /LICENSE for more information.
@@ -8,13 +8,12 @@
 include $(TOPDIR)/rules.mk
 
 PKG_NAME:=gmp
-PKG_VERSION:=6.0.0
-PKG_REVISION:=a
+PKG_VERSION:=6.1.0
 PKG_RELEASE:=1
 
 PKG_SOURCE:=$(PKG_NAME)-$(PKG_VERSION)$(PKG_REVISION).tar.xz
-PKG_SOURCE_URL:=http://gmplib.org/download/gmp/
-PKG_MD5SUM:=1e6da4e434553d2811437aa42c7f7c76
+PKG_SOURCE_URL:=@GNU/gmp/
+PKG_MD5SUM:=a9868ef2556ad6a2909babcd1428f3c7
 
 PKG_BUILD_PARALLEL:=1
 PKG_INSTALL:=1