Add initial support to trace spawned threads in a process on Linux.

llvm-svn: 171864
diff --git a/lldb/source/Plugins/Process/POSIX/ProcessMessage.cpp b/lldb/source/Plugins/Process/POSIX/ProcessMessage.cpp
index a8b8e95..cefacc3 100644
--- a/lldb/source/Plugins/Process/POSIX/ProcessMessage.cpp
+++ b/lldb/source/Plugins/Process/POSIX/ProcessMessage.cpp
@@ -224,6 +224,9 @@
     case eCrashMessage:
         str = "eCrashMessage";
         break;
+    case eNewThreadMessage:
+        str = "eNewThreadMessage";
+        break;
     }
 #endif