DEBUG_AS_DEFAULT

[Jean-Marc Lasgouttes]

Hello there,

I was about to remove the --with-debug flag of configure and noticed
that Allan has actually been using DEBUG_AS_DEFAULT in bullet code.
Wouldn't it make sense to condition on DEVEL_VERSION instead? At least
we would be sure that the invariants are actually tested.

Another solution would be to add an --enable-assertions flag which
defaults to 'yes' for development versions, but which can be turned
off (for speed reasons).

What do you think?

JMarc