Fix the build of the wasm backend.

toString conflicts with llvm::toString here. Yay for overly generic
function names.

llvm-svn: 325833
diff --git a/llvm/lib/Target/WebAssembly/InstPrinter/WebAssemblyInstPrinter.cpp b/llvm/lib/Target/WebAssembly/InstPrinter/WebAssemblyInstPrinter.cpp
index c3f0f27..73d9b3d 100644
--- a/llvm/lib/Target/WebAssembly/InstPrinter/WebAssemblyInstPrinter.cpp
+++ b/llvm/lib/Target/WebAssembly/InstPrinter/WebAssemblyInstPrinter.cpp
@@ -176,10 +176,10 @@
     if (Info.OperandType == WebAssembly::OPERAND_F32IMM) {
       // TODO: MC converts all floating point immediate operands to double.
       // This is fine for numeric values, but may cause NaNs to change bits.
-      O << toString(APFloat(float(Op.getFPImm())));
+      O << ::toString(APFloat(float(Op.getFPImm())));
     } else {
       assert(Info.OperandType == WebAssembly::OPERAND_F64IMM);
-      O << toString(APFloat(Op.getFPImm()));
+      O << ::toString(APFloat(Op.getFPImm()));
     }
   } else {
     assert((OpNo < MII.get(MI->getOpcode()).getNumOperands() ||