This patch changes the default behavior of how KOS is kept around by installing the headers and libraries to a path defined in environ.sh. KOS_BASE is no more and in Makefiles for projects should be updated to include ${KOS_BASE}/scripts/Makefile.rules.
All Dreamcast examples have been changed to work with the installed KOS. The Gba and Ps2 examples have been changed but are untested.
As a side note this patch also deletes addons/lib/.keepme which seems like a legacy file that's just stuck around till now.
I've tested this pretty well in Linux only with Dreamcast. I'm not sure if there's going to be any strangeness with OS X or Windows. I'll try to get a toolchain built in both of those environments.
Finally, this patch is to be used with the Make KOS Ports Installable patch.