Linux crash native stacks only have 1 line

[Alexander Miloslavskiy]

Hmm, after trying to cobble something together with `_Unwind_Backtrace`, 
I found that it's not going to be too easy: it's undocumented, so will 
be subject to trial&error, which doesn't sound too good.

Back to libunwind, I noticed that its license says:
----
Permission is hereby granted, free of charge, to any person obtaining
a copy of this software and associated documentation files (the
"Software"), to deal in the Software without restriction, including
without limitation the rights to use, copy, modify, merge, publish,
distribute, sublicense, and/or sell copies of the Software, and to
permit persons to whom the Software is furnished to do so, subject to
the following conditions:

The above copyright notice and this permission notice shall be
included in all copies or substantial portions of the Software.
----

Is that really a licensing problem for JDK?