developing c++ xpcom component

[A Sh]

i followed and read

https://developer.mozilla.org/en-US/Add-ons/Creating_Custom_Firefox_Extensions_with_the_Mozilla_Build_System

https://wiki.mozilla.org/Education/Learning/XpcomComponents

but it doesnt work as cleanly on release version 29 for firefox

i downloaded and build firefox source code on the ubuntu
However my extension doesnt get picked up after step - https://wiki.mozilla.org/Education/Learning/XpcomComponents#Building_FirstXpcom

on this wiki there is a step $ cd $(objdir)
$ ../build/autoconf/make-makefile extensions/firstxpcom i dont know what does that mean
so i used

$ cd mozilla
$ make -f client.mk build

Are there any updated steps.. since all docs i found are 2005 2009 written?

Can someone help?