Use set directive for StartMinusEndExpr.
This is a fix for llvm-gcc-i386-darwin9 buildbot failure.

llvm-svn: 120742
diff --git a/llvm/lib/MC/MCNullStreamer.cpp b/llvm/lib/MC/MCNullStreamer.cpp
index c781fe6..c79793c 100644
--- a/llvm/lib/MC/MCNullStreamer.cpp
+++ b/llvm/lib/MC/MCNullStreamer.cpp
@@ -66,7 +66,7 @@
     virtual void EmitBytes(StringRef Data, unsigned AddrSpace) {}
 
     virtual void EmitValue(const MCExpr *Value, unsigned Size,
-                           unsigned AddrSpace) {}
+                           unsigned AddrSpace, bool UseSet = false) {}
     virtual void EmitULEB128Value(const MCExpr *Value,
                                   unsigned AddrSpace = 0) {}
     virtual void EmitSLEB128Value(const MCExpr *Value,