Author: Holger Jaekel <holger.jaekel@gmx.de>
Summary: convert Aws::StringStream to std::string
----

--- a/tiledb/sm/filesystem/s3.cc
+++ b/tiledb/sm/filesystem/s3.cc
@@ -212,7 +212,7 @@
 
   ss << " : " << err.GetMessage();
 
-  return ss.str();
+  return ss.str().c_str();
 }
 
 }  // namespace