* doc/8sync.texi: New text in 8sync license section.
The short version of this is that if you distribute a modifications to
8sync, whether alone or in some larger combination, must release the
corresponding source code.
+A program which uses this library, if distributed without source code,
+ must also allow relinking with a modified version of this library.
In general, it is best to contribute them back to 8sync under the same terms;
we'd appreciate any enhancements or fixes to be contributed upstream to
8sync itself.