Mention more debug symbol flags

Author: bernhardmgruber

talk/tools/compiling.tex

@@ -70,7 +70,7 @@
   \end{block}
   \begin{block}{Optimization}
     \begin{description}
-      \item[-g] add debug symbols
+      \item[-g] add debug symbols (also: \texttt{-g3} or \texttt{-ggdb})
       \item[-Ox] 0 = no opt., 1-2 = opt., 3 = highly opt. (maybe larger binary), g = opt. for debugging
     \end{description}
   \end{block}