gnutls 3.x requires nettle.

component/gnutls/buildout.cfg

 [buildout]
 extends =
-  ../readline/buildout.cfg
+  ../gmp/buildout.cfg
+  ../nettle/buildout.cfg
   ../ncurses/buildout.cfg
+  ../readline/buildout.cfg
   ../zlib/buildout.cfg
 
 parts = gnutls
@@ -22,7 +24,6 @@ environment =
   LDFLAGS=-lgpg-error -L${gpg-error:location}/lib -Wl,-rpath=${gpg-error:location}/lib
 
 [gnutls]
-# XXX-Cedric : update to latest gnutls
 recipe = slapos.recipe.cmmi
 url = ftp://ftp.gnutls.org/gcrypt/gnutls/v3.2/gnutls-3.2.0.tar.xz
 md5sum = e0cba4ddd923420026ff9739b3bc069a
@@ -30,6 +31,6 @@ configure-options =
   --with-libgcrypt-prefix=${gcrypt:location}
   --disable-static
 environment =
-  CPPFLAGS=-I${zlib:location}/include -I${readline:location}/include -I${ncurses:location}/include -I${ncurses:location}/include/ncursesw -I${gcrypt:location}/include -I${gpg-error:location}/include
-  LDFLAGS=-lgcrypt -L${readline:location}/lib -Wl,-rpath=${readline:location}/lib -L${ncurses:location}/lib -Wl,-rpath=${ncurses:location}/lib -L${gcrypt:location}/lib -Wl,-rpath=${gcrypt:location}/lib -L${zlib:location}/lib -Wl,-rpath=${zlib:location}/lib -L${gpg-error:location}/lib -Wl,-rpath=${gpg-error:location}/lib
-  PKG_CONFIG=${zlib:location}/lib/pkgconfig
+  CPPFLAGS=-I${zlib:location}/include -I${readline:location}/include -I${ncurses:location}/include -I${ncurses:location}/include/ncursesw -I${gmp:location}/include -I${gcrypt:location}/include -I${gpg-error:location}/include -I${nettle:location}/include
+  LDFLAGS=-lgcrypt -L${gmp:location}/lib -Wl,-rpath=${gmp:location}/lib -L${readline:location}/lib -Wl,-rpath=${readline:location}/lib -L${ncurses:location}/lib -Wl,-rpath=${ncurses:location}/lib -L${gcrypt:location}/lib -Wl,-rpath=${gcrypt:location}/lib -L${nettle:location}/lib -Wl,-rpath=${nettle:location}/lib -L${zlib:location}/lib -Wl,-rpath=${zlib:location}/lib -L${gpg-error:location}/lib -Wl,-rpath=${gpg-error:location}/lib
+