Provide LinuxThread with an implementation of Thread::GetUnwinder.

llvm-svn: 122841
diff --git a/lldb/source/Plugins/Process/Linux/LinuxThread.h b/lldb/source/Plugins/Process/Linux/LinuxThread.h
index afa1548..0e7f89d 100644
--- a/lldb/source/Plugins/Process/Linux/LinuxThread.h
+++ b/lldb/source/Plugins/Process/Linux/LinuxThread.h
@@ -78,6 +78,9 @@
 
     lldb::StopInfoSP
     GetPrivateStopReason();
+
+    lldb_private::Unwind *
+    GetUnwinder();
 };
 
 #endif // #ifndef liblldb_LinuxThread_H_