gnutls: fix link-time build failures

Fixes
http://autobuild.buildroot.net/results/23da17446266bdd49ea0da0c1892d66d3ac6607f/build-end.log
And may the <BEEP> rest in peace at last...

Signed-off-by: Gustavo Zacarias <gustavo@zacarias.com.ar>
Acked-by: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>
Signed-off-by: Peter Korsgaard <jacmet@sunsite.dk>

package/gnutls/gnutls.mk

@@ -10,8 +10,9 @@ GNUTLS_SITE = $(BR2_GNU_MIRROR)/gnutls
 GNUTLS_LICENSE = GPLv3+ LGPLv2.1+
 GNUTLS_LICENSE_FILES = COPYING lib/COPYING
 GNUTLS_DEPENDENCIES = host-pkg-config libgcrypt $(if $(BR2_PACKAGE_ZLIB),zlib)
+GNUTLS_CONF_ENV = acl_cv_rpath=no
 GNUTLS_CONF_OPT = --with-libgcrypt --without-libgcrypt-prefix \
-		--without-p11-kit
+		--without-p11-kit --disable-rpath
 GNUTLS_INSTALL_STAGING = YES
 
 $(eval $(autotools-package))