gnutls: fix crosscompile build

building x86 fails with
sha-padlock.c:355:49: error: 'sha1' undeclared here (not in a function)
 const struct nettle_hash padlock_sha1 = NN_HASH(sha1, padlock_sha1_update, padlock_sha1_digest, SHA1);

CPP macro NN_HASH in x86.h was not used/detected by autoconf
explicitly set it

Signed-off-by: Dirk Neukirchen <dirkneukirchen@web.de>
gnutls: disable rpath

disable rpath
Other cross environments like Buildroot [1], OpenEmbedded [2]
disable it too, so do the same

[1]http://git.buildroot.net/buildroot/tree/package/gnutls/gnutls.mk
[2]http://git.openembedded.org/openembedded-core/tree/meta/recipes-support/gnutls/gnutls.inc

Signed-off-by: Dirk Neukirchen <dirkneukirchen@web.de>