1. Previous SW configuration for different RRC version relies on whether macro Rel10,
   Rel14 defined or not by checking #ifdef Rel14 or #if defined(Rel10) || defined(R14).
   Whenever there is a newer RRC version, e.g. Rel15, it will be very a tedious and
   error-prone job to add defined(Rel15) in every place.

2. Some RRC messages are defined in release 13 instead of release 14, NB-IoT
   feature is one of such example. Our code shall reflect this fact instead of using
   an afterward version number in software configuration.

3. Some RRC messages or some fields of certain RRC messages are added in the middle
   a release, e.g. SystemInformationBlockType1_v1310_IEs_t defined in RRC 13.1.0
   and RRC 9.2.0 made some changes to SIB12 and SIB13 so we have sib12_v920 and
   sib13_v920 fields in SIB12 and SIB13's struct.
   We need a finer grain of control when using ASN1 from different RRC version.

4. S1AP also has this problem that it use UPDATE_RELEASE_9 and UPDATE_RELEASE_10 to
   differentiate between various S1AP version.

This commit propose using MAKE_VERSION(x,y,z) to designate the version number and
modify current conditional compilation accordingly.

Note: 2018/04/16, Modified based on Cedric's comment.

- fix compilation of dlsim/ulsim/oaisim by defining some needed
  global variables
- fix compilation of oaisim: compile coding and params_libconfig
- fix running of if4p5 with low CPU count (oaisim was not working
  on the machine 'haswell' because of this)

modifications for simulator : power normalizations for UE TX, small changes to SNR targets for power control, default UE power (23 dBm now)

This is only needed by the UE code, to setup IP settings.
The eNB does not need this. (To be reverted if this is
wrong.)

It is possible to restart the lte-softmodem via the FlexRAN controller. For
this to work, the end_configmodule() method needs to be called when shutting
the lte-softmodem down so that the configuration can be read again during a
restart.

When the program exits it has to stop the streaming of the USRP.
The function exit_fun is supposed to do that. When quitting with
control+c (very common case) this function is not called. The
code is very unclear there, so let's add a stop_rf in the RU,
as there is already a start_rf.

If we don't call trx_end_func, then at the next run the USRP
device may be in an unstable state and behave improperly.

If the program crashes then the USRP device may be in an
unstable state. The only solution to this problem is to reset
the USRP device.

Maybe there is a way to clean the state of the device when we
open it, before we start using it. Sort of a cleanup before
use. That could be a better solution to "bad state after program
crash".

What has been tested:
- monolithic eNB only

The one in lte-enb.c disrupts the realtime. Using a B200mini with
20MHz bandwidth leads to the UE unable to connect for it seesms like
the UL and DL are not properly time synched because of this sleep
of one second that happens after the USRP streaming has started.
We see some random access attempts but the decoded preamble is
wrong.

This may be dependant on the setup. I had sporadic errors with
a B210, where sometimes the UE could connect and sometimes not.

the functions are meant to restart the lte-softmodem (lower layers) and are not
supported in oaisim. They are provided to make oaisim compile.

I tried to change rx and tx attenuation by the config file, but they are not changed. The bug is because att_rx and att_tx do not put in RC.rru when local_rf is "yes" in config file. We need to put att_rx and att_rx for both local_rf = "yes" and "no". Also RF config which send to RF device must be fill by this parameters.