Debian and the FSF have different positions on the GFDL.
Consequently, the GDB release tarball includes GFDL documents which
must go in the Debian non-free section.

To produce the necessary tarballs, download an official GDB release as
.tar.bz2 from the FSF.  Run debian/sanitize-gdb.sh on it.  That
will produce a gdb .orig.tar.xz and a gdb-doc .orig.tar.xz

 -- Samuel Bronson <naesten@gmail.com>, Sat,  3 May 2014 17:22:31 -0400