Bug#781375: libgnutls28-dev: cannot install

[root]

Package: libgnutls28-dev
Severity: critical
Justification: breaks unrelated software

Dear Maintainer,

   I tried to install the packages to compile Samba 4.2, this usually 
   means installing libgnutls-dev, but this seems to have been replaced
   by libgnutls28-dev, YOU CANNOT INSTALL THIS!

The following packages have unmet dependencies:
libgnutls28-dev : 
Depends: libgnutls-deb0-28 (= 3.3.8-6~bpo70+1) but 3.3.8-6 is to be installed
Depends: libgnutlsxx28 (= 3.3.8-6~bpo70+1) but it is not going to be installed
Depends: nettle-dev (>= 2.5) but it is not going to be installed
Depends: libtasn1-6-dev (>= 3.9) but it is not going to be installed
Depends: libp11-kit-dev (>= 0.20.7) but it is not going to be installed
libldap2-dev : 
Depends: libldap-2.4-2 (= 2.4.31+really2.4.40-4~bpo70+1) but 2.4.40-4 is to be installed

tried to add a few of the above, but:

The following packages have unmet dependencies:
libgnutls28-dev : Depends: 
libgnutls-deb0-28 (= 3.3.8-6~bpo70+1) but 3.3.8-6 is to be installed
libgnutlsxx28 : Depends: 
libgnutls-deb0-28 (= 3.3.8-6~bpo70+1) but 3.3.8-6 is to be installed
libldap2-dev : Depends: 
libldap-2.4-2 (= 2.4.31+really2.4.40-4~bpo70+1) but 2.4.40-4 is to be installed
libp11-kit-dev : Depends: 
libp11-kit0 (= 0.20.7-1~bpo70+1) but 0.20.7-1 is to be installed
libtasn1-6-dev : Depends: 
libtasn1-6 (= 4.2-2~bpo70+1) but 4.2-2 is to be installed
Recommends: libtasn1-doc (= 4.2-2~bpo70+1) but it is not going to be installed
nettle-dev : Depends: 
libnettle4 (= 2.7.1-1~bpo70+1) but 2.7.1-5 is to be installed
Depends: libhogweed2 (= 2.7.1-1~bpo70+1) but 2.7.1-5 is to be installed

I gave up at this point!!!

-- System Information:
Debian Release: 8.0
  APT prefers testing-updates
  APT policy: (500, 'testing-updates'), (100, 'testing')
Architecture: amd64 (x86_64)

Kernel: Linux 3.16.0-0.bpo.4-amd64 (SMP w/1 CPU core)
Locale: LANG=en_GB.UTF-8, LC_CTYPE=en_GB.UTF-8 (charmap=UTF-8)
Shell: /bin/sh linked to /bin/dash
Init: systemd (via /run/systemd/system)