re-adding the possibility in dlsim to bypass the DCI/PDCCH generation. This is necessary for accuracy of the dlsim-tests, which are working again now.

Problems reported by Jorge Muñoz Castañer <jorgem@gti.uvigo.es>.

- use Rel14 binaries (those are produced by default)
- let -x option work to have graphical output
- fix VCD missing 'echo'

Discovered and fix problems in shared lib build for usrp,bladerf and lime

The presence of one or the other may lead to some failure/crash in
some situations.

The files NativeInteger.c.diff and constr_SET_OF.c.diff
from asn1c were generating compilation warnings. We had
local patches applied on generated files by asn1c.

A new version of asn1c has been pushed to
https://gitlab.eurecom.fr/oai/asn1c
(commit 224dc1f991b7e7ad705ce92e171b942f87b7b7e7)
making obsolete the fixes we do here.

So we now remove those fixes.

*************************
* IMPORTANT BEGIN       *
*************************

Everyone should update their asn1c installation.

The simplest is to do:

    source oaienv
    cd cmake_targets
    ./build_oai -I

*************************
* IMPORTANT END         *
*************************

- import RRC ASN.1 defintions from the specifications
  (file openair2/RRC/LITE/MESSAGES/asn1c/ASN1_files/RRC-e10.asn)
  contrary to rel8/10, all modules have been imported, maybe it's too much
  to refine in case of problems
- deal with rel14 in fix_asn1
- all code that was for Rel10 is now for Rel10/Rel14
- some incompatible changes (mostly in naming) were resolved in favor
  of rel14, see in openair2/RRC/LITE/defs.h
- unsure about the rlc layer, some arrays have changed (values appended),
  I only changed the definition and in tests in the code, I changed
  the index limit, maybe it's not enough

Rel14 is the default compilation mode.

see oai/openairinterface5g#227

When the UE connects to the eNodeB and receives its IP address from the
network, it calls system() to set it in the linux kernel world. This call
is not done in a realtime thread, but in the NAS, which uses its own thread,
independent of the realtime processing.

In some situations this totally disrupts realtime processing.

It is difficult to know precisely why that happens, but it seems that calling
fork(), as system() does, in a multi-threaded program is not a good idea. (So
say several people on the internet.) It is not clear why the softmodem is
impacted, but it seems that fork() is really what triggers the disruption.
Several tests lead to that conclusion.

To fix the problem, we create a child background process very early in main()
(before anything else basically). Then instead of calling system(), the main
process sends the string to the background process. The background process
gets the string, passes it to system() and reports the success/failure back
to the main process.

This solution involves a lot of system calls, but calling system() in the
first place is not cheap either. As long as no realtime thread uses this
mechanism, things should be fine. Time will tell.

- README.txt modified
- tests added in test_case_list.xml
  (only for test setup v2)
- python code modified
- configuration files added

This work was done by Laurent Thomas.

On some hosts, compilations with the T tracer was failing.

The error was:
  common/utils/T/T.h:15:19: fatal error: T_IDs.h: No such file or directory

The problem was that in CMakeLists.txt some targets depend on the
pre-generation of T_IDs.h but this dependancy relation was not set,
so those targets could be generated before the T (it was the case
with HASHTABLE).

This commit fixes that. Basically, we take all the targets found in
"add_executable" and "add_library" and make them depend on the
T if the T is enabled. Almost all existing targets were added,
even those that may not need it.

The problem of this approach is that someone adding a new target
using the T will not necessarily add a dependancy there.

Another solution would be to generate T_IDs.h at "cmake" stage,
not "make" stage and use an "if (NOT EXISTS T_IDs.h)" to generate
the file. We lose the dependancy relation though.

Things may be changed if maintenance cost is too high.

New tests: 0186xx for TDD with the huawei 3276 dongle.
All necessary files to configure and use it have been added.
Existing code has been adapted for the TDD tests.
Only the test setup v2 has been adapted.
The file test_case_list.xml has been changed to add tests
0186xx, but only to work with test setup v2. It won't
work with test setup v1. To be completed if needed.

The tests are similar to FDD tests.
Throughputs for TDD have to be adjusted, the throughputs
of FDD are used for the moment.

Let the user see how many warnings a compilation generates.
The goal is to have 0 warning, for any compiled component
of openair.

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.