Fix Linux by partially reverting 196787

llvm-svn: 197065
diff --git a/lldb/source/Plugins/Process/POSIX/POSIXThread.h b/lldb/source/Plugins/Process/POSIX/POSIXThread.h
index a59a3a7..51d6645 100644
--- a/lldb/source/Plugins/Process/POSIX/POSIXThread.h
+++ b/lldb/source/Plugins/Process/POSIX/POSIXThread.h
@@ -79,6 +79,8 @@
     //--------------------------------------------------------------------------
     // These methods form a specialized interface to POSIX threads.
     //
+    bool Resume();
+
     void Notify(const ProcessMessage &message);
 
     //--------------------------------------------------------------------------