* Check the first argument for "help" as well. If given print a somewhat
helpful text. Consider this my excuse to close ticket #1883. :-)
* Track available and added optional packages and fail, if an optional package
is requested that doesn't exist. Closes ticket #3332.
* Check for duplicate build profile definitions and fail if encountered.
Closes ticket #3333.
git-svn-id: file:///srv/svn/repos/haiku/haiku/trunk@29298 a95241bf-73f2-0310-859d-f6bbb57e9c96
