libroot: Import a lot of changes to stdlib, string code from FreeBSD. Includes licensing clause removal. Also deleted 2 files that are not used in the build and are not referenced anywhere else.
Renamed src/kernel to src/system. git-svn-id: file:///srv/svn/repos/haiku/haiku/trunk@12359 a95241bf-73f2-0310-859d-f6bbb57e9c96