* the libbe_build version of BString was broken, at least with respect
to LockBuffer() on an empty string - replaced the implementation and
header with our current version (keeping the type-related changes
required by the build-version)
git-svn-id: file:///srv/svn/repos/haiku/haiku/trunk@40526 a95241bf-73f2-0310-859d-f6bbb57e9c96
