* gnu/packages/patches/gnutls-fix-duplicate-manpages.patch: New file.
* gnu-system.am (dist_patch_DATA): Add it.
* gnu/packages/gnutls.scm (gnutls)[source]: Update to 3.4.0. Add patch.
[arguments]: Pass --without-p11-kit to 'configure'.
[propagated-inputs]: Use 'nettle' instead of 'nettle-2'. Add 'libidn'.