added 2 missing brew dependencies that broke the bootstrap.sh script.
revert changes on config.guess, the bootstrap script changed this file, perhaps shouldn't be in repo
silenced unused variable warnings.
make sure BDB_INCLUDE_PATH is in the PATH for Mac users as it can be in conflict with existing BDB installation.
merging last changes from original repository
printf call expects long int
Merge pull request #75 from gubatron/osx-env-warning-cleanups-doc-updates

OSX build documentation updates, cleanups, warning suppression.
Merge pull request #78 from toyg/fix_build_warnings

libtorrent printf call expects long int
nothing interesting, just checkpointing + warning fix