Unbreak Clang build after r191050: don't pass a StringRef to snprintf.

llvm-svn: 191062
diff --git a/llvm/lib/DebugInfo/DWARFContext.cpp b/llvm/lib/DebugInfo/DWARFContext.cpp
index db0d21f..cbc1d5a 100644
--- a/llvm/lib/DebugInfo/DWARFContext.cpp
+++ b/llvm/lib/DebugInfo/DWARFContext.cpp
@@ -135,8 +135,9 @@
         break;
       PubIndexEntryDescriptor desc(pubNames.getU8(&offset));
       OS << format("0x%8.8x ", dieRef)
-         << format("%-8s", dwarf::GDBIndexEntryLinkageString(desc.Linkage))
-         << ' ' << dwarf::GDBIndexEntryKindString(desc.Kind) << " \""
+         << format("%-8s", dwarf::GDBIndexEntryLinkageString(desc.Linkage)
+                               .str().c_str()) << ' '
+         << dwarf::GDBIndexEntryKindString(desc.Kind) << " \""
          << pubNames.getCStr(&offset) << "\"\n";
     }
   }