Add AsmParser support for darwin tbss directive.

Nothing uses this yet.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@103757 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/MC/MCNullStreamer.cpp b/lib/MC/MCNullStreamer.cpp
index 8bde2d9..c206bb3 100644
--- a/lib/MC/MCNullStreamer.cpp
+++ b/lib/MC/MCNullStreamer.cpp
@@ -55,7 +55,8 @@
 
     virtual void EmitZerofill(const MCSection *Section, MCSymbol *Symbol = 0,
                               unsigned Size = 0, unsigned ByteAlignment = 0) {}
-
+    virtual void EmitTBSSSymbol(MCSymbol *Symbol, uint64_t Size,
+                                unsigned ByteAlignment) {}
     virtual void EmitBytes(StringRef Data, unsigned AddrSpace) {}
 
     virtual void EmitValue(const MCExpr *Value, unsigned Size,