SDK 2.1 - Makefile options


I am using CUDA SDK 2.1. I noticed that when I build a project the Makefiles use -O3 by default. Is there a variable I can define when I invoke make so it uses -O2?

And, in a more general aspect, is there a document describing the options that I can pass to the Makefiles. For example, I know you can run ‘make keep=1’ to keep the intermediate files. Where is this documented (beside having to follow Makefiles all over the SDK)? I tried /doc and the FAQ in the forums but didn’t see anything.

Thank you,