Petr Kadlec:
Note that it is also possible some tools _cannot_ be
freely licensed,
because they contain/use third-party code/libraries not under a free
license.
This is only the case if they actually derive the third-party code. Just
linking to it is fine (possibly not for GPL, but for more reasonable
licenses). (There are also open source licenses that allow licensed code to
be mixed with non-free code in the same executable, as long as it's not in
the same file.)
Even so, if the tool is using the library in the first place, it should be
possible to construct a license that allows distribution and modification,
even if it's not a fully free license. The only time this isn't possible is
if the code were licensed to only a single person, which I imagine should be
quite unlikely.
(Example: a tool using code that only allows non-commercial use cannot be
open source, but it can still be licensed in a way that allows it to be
shared amongst Toolserver and other users.)
- river.