In the webkit plugin, don't try to load web browser plugins except on Windows. The flash plugin on the Mac crashes the webkit plugin when running under xcode.
svn merge -r 129913:131718 svn+ssh://svn.lindenlab.com/svn/linden/branches/pluginapi/pluginapi_05
Some branch shenannigans in the pluginapi_05 branch caused this to become a two-part merge.
Monroe Williams