Rename NeedsSetToChangeDiffSize to HasAggressiveSymbolFolding which is a much
better name and matches what is used in the MachO writer.

llvm-svn: 122443
diff --git a/llvm/lib/MC/MCStreamer.cpp b/llvm/lib/MC/MCStreamer.cpp
index 076b4d6..68146de 100644
--- a/llvm/lib/MC/MCStreamer.cpp
+++ b/llvm/lib/MC/MCStreamer.cpp
@@ -77,7 +77,7 @@
 
 void MCStreamer::EmitAbsValue(const MCExpr *Value, unsigned Size,
                               unsigned AddrSpace) {
-  if (!getContext().getAsmInfo().needsSetToChangeDiffSize()) {
+  if (getContext().getAsmInfo().hasAggressiveSymbolFolding()) {
     EmitValue(Value, Size, AddrSpace);
     return;
   }