Index: lib/Driver/Tools.cpp
===================================================================
--- lib/Driver/Tools.cpp	(revision 117606)
+++ lib/Driver/Tools.cpp	(working copy)
@@ -2566,6 +2566,9 @@
   CmdArgs.push_back("-o");
   CmdArgs.push_back(Output.getFilename());
 
+  // Claim -pthread here: be permissive (e.g. when linking a binary)
+  (void) C.getArgs().hasArg(options::OPT_pthread);
+   
   if (!Args.hasArg(options::OPT_A) &&
       !Args.hasArg(options::OPT_nostdlib) &&
       !Args.hasArg(options::OPT_nostartfiles)) {
