You're on Linux right? Well.. in my Windoze machine it takes 20-40 minutes to compile CB and it's contrib items.
If I had warnings enabled, it would take more then 3 hours because of that warning spam I get... (and the fact that Windoze is slow as hell... especially in terms of console output^^)
As I'm always using the latest GCC, I was probably one of the first ones who have seen all these numerous warnings. It all started with GCC 4.8.. before that, the warnings were few and not really important. (I don't know how much impact they had...)
Anyway.. none the less it would be nice to see you guys not ignoring these warnings and instead fixing them
Actually they all have their reasons and it's way easier once you've got rid of them. As then, every warning will be a single one caused by recent changes and is easy to see and fix.