ch01-02-hello-orbtk: hint on build with debug information

Signed-off-by: Ralf Zerres <ralf.zerres@networkx.de>

src/ch01-02-hello-orbtk.md

@@ -284,4 +284,9 @@ On Windows, you need to use `backslash` as a path delimeter:
 > ..\target\release\hello_orbtk.exe
 ```
 
+If you like to get debug feedback you can call the build process like this
+
+```console
+$ cargo build --features debug --bin hello_orbtk.rs
+```
 [troubleshooting]: ch01-01-installation.html#troubleshooting