[WebAssembly] Define toString(wasm::InputChunk *) and use that in MarkLive.cpp.

Define toString(wasm::InputChunk *) and use that in MarkLive.cpp.

Differential Revision: https://reviews.llvm.org/D43434

llvm-svn: 325535
diff --git a/lld/wasm/InputChunks.h b/lld/wasm/InputChunks.h
index e9d86f0..388e3b9 100644
--- a/lld/wasm/InputChunks.h
+++ b/lld/wasm/InputChunks.h
@@ -174,6 +174,8 @@
 };
 
 } // namespace wasm
+
+std::string toString(const wasm::InputChunk *);
 } // namespace lld
 
 #endif // LLD_WASM_INPUT_CHUNKS_H