[ELF2] Add support for -discard-none.

Differential Revision:	http://reviews.llvm.org/D13083

llvm-svn: 248499
diff --git a/lld/ELF/Driver.cpp b/lld/ELF/Driver.cpp
index 9d487ad..deafb6a 100644
--- a/lld/ELF/Driver.cpp
+++ b/lld/ELF/Driver.cpp
@@ -88,6 +88,9 @@
   if (Args.hasArg(OPT_discard_locals))
     Config->DiscardLocals = true;
 
+  if (Args.hasArg(OPT_discard_none))
+    Config->DiscardNone = true;
+
   if (Args.hasArg(OPT_export_dynamic))
     Config->ExportDynamic = true;