When rebuilding oaisim, I had a failure because the target
link already exists. The -f flag forces the link to be done.

- build script has ability to indicate location for downloading uhd images
- one simple wrapper to set environment variables and initiate another program (supposed to be lte-softmodem)

This reverts commit d31634c3.

Laurent Thomas had a problem on one machine with the build_oai
way of checking for nettle.

The problem with the alternative solution of including nettle/bignum.h
is that it is very unclear.

The problem with nettle is that the file nettle/config.h does not
exist for version 2. It was introduced in version 3.

We want to support both versions, but there is an API incompatibility.
So we need an #if #else mechanism.

The file nettle/bignum.h is present in both versions 2 and 3 and it
includes nettle/version.h in the version 3.

So by including this file, we can check for the existence of
NETTLE_VERSION_MAJOR (that comes from nettle/config.h) in the
code.

But as you can see, the reasoning is way too complex.

So it's better to keep the check in cmake_targets/CMakeLists.txt.

As long as we support version 2 this will be the way to go.

It is possible to force a given version in specific non-generic
customized environments.

- the option --UE was abused! Let's introduce --UE-conf-nvram and
  --UE-gen-nvram
- the option name --UE-OUTPUT was not clear and is now replaced by
  --UE-gen-nvram
- the new options are described when running ./build_oai -h
- print_help has been modified (' replaced by ") to print
  $conf_nvram_path and $gen_nvram_path

All the test pass.

The previous version did not compile on ubuntu 16.04.
I left the old version, commented, just in case.

In openairinterface5g many definitions in many layers of UE or eNB NB_MAX.
We created a file called openairinterface5g_limits.h
located at openairinterface5g_dir/targets/COMMON/ declaring the number max
of UE and eNB to be used in ALL layers depending on launching conditions
(LARGE_SCALE for example).

This commit reverts behaviour of data generation as before
commit 7207c65b05fd812a18371827f2bfb1431fc58696:

    fix .ue* filenames in scripts and documentation

    TODO add option to conf2uedata and adapt script

TODO add option to conf2uedata and adapt script

This patch adds the conf2uedata tool for generating .ue.nvram* .ue.emm.nvram*
and .usim.nvram* files from a textual configuration file.

The configuration file define most usefull values like plmns, mnc, mcc, msin, K,
OPc for several users.
The files generated will always ends with a number corresponding to the user
entry in the configuration file.

This breaks oai5g because other script have not be updated for using
conf2uedata.
This breaks also the at_nas_ue command.

Examples of configuration files are in openair3/NAS/TOOLS/

The compilation of this module does not seem to be necessary,
as far as I have checked. Plus it fails when you run
"build_oai --oaisim --noS1", so let's not compile it.

when testing on haswell, using apt-get to install LimeSDR
libraries and includes, it put it in /usr/include, not
/usr/local/include

init_nas_s1 may not work properly, but many people complain
about this file, so let's put it in the repository.

We'll fix it at some point if it's not properly usable.

The throughput for the bandrich dongle was limited to 13Mb/s in downlink
UDP with iperf, with lots of packets lost (we sent 15Mb/s). TCP was
working fine.

Replacing /dev/ttyUSB2 by /dev/ttyUSB0 for wvdial solves the issue.

We also had to have separate data/control links. (See bandrich.txt
in cmake_targets/autotests/v2/actions for full details.)

The old one is still usable by replacing .gitlab-ci.yml with
the previous version.

As reported on the mailing list, there was a problem
for some users. The link phase of building the simulators
was giving the error "undefined reference to ATL_scopy".