For building firefox I started the process following the instruction on [http://annasob.wordpress.com/category/build/ annasob's blog] and from [https://developer.mozilla.org/En/Developer_Guide/Build_Instructions Mozilla Developing Center(MDC)]Here are the information that were useful for me to get the set of instructions and to figure out how to deal with errors.One thing that was really helpful to me was annasobanna's tip on separating mozilla-build (where the build package is installed) and mozilla-central(where the source is cloned from Mozilla repository).