libunwind: use url alias

Use alias instead of hardcoded URL

Signed-off-by: Daniel Engberg <daniel.engberg.lists@pyret.net>

package/libs/libunwind/Makefile

@@ -12,7 +12,7 @@ PKG_VERSION:=1.1
 PKG_RELEASE:=1
 
 PKG_SOURCE:=$(PKG_NAME)-$(PKG_VERSION).tar.gz
-PKG_SOURCE_URL:=http://download.savannah.gnu.org/releases/libunwind
+PKG_SOURCE_URL:=@SAVANNAH/$(PKG_NAME)
 PKG_MD5SUM:=fb4ea2f6fbbe45bf032cd36e586883ce
 PKG_FIXUP:=autoreconf
 PKG_INSTALL:=1