The command line to get the error was:
    ./build_oai --eNB -w EXMIMO -c

The command line to get the error was:
    ./build_oai --eNB -w EXMIMO -c

The compilation line was:
    ./build_oai --eNB -w USRP

The file openairinterface5g/cmake_targets/log/lte-softmodem.Rel10.txt
has been checked and all LOG_X (and 'msg') warnings have been fixed.

- some cleanup
- thread names to include UE Mod_id
- arg of UE_thread_rxn_txnp4 to be struct rx_tx_thread_data again
- sync in UE_thread_rxn_txnp4 to use instance_cnt_rxtx again
- UE_thread to call itti_send_msg_to_task with UE->Mod_id + NB_eNB_INST
  instead of INSTANCE_DEFAULT again

This may break the softmodem UE, to be tested.
The most problematic thing may be the synchronization.
I don't think it will impact the processing at all,
but I won't bet my shirt on it.

git show -p 58052152
to see what it's about

git show 157707b0
to see what it's about

Many variables were changed that should not have been changed.

Guess what happens when we return from the function...

For whatever reason, lte-softmodem.c was totally messed up...

We took the version from the branch develop and added
abstraction_flag, which is needed in openair2/LAYER2/MAC/main.c
(this is not clean, previous commit added a comment for this).
This has to be cleaned at some point.

The idea is as follows.

oaisim waits for all tasks to be done for a TTI.
To do so it waits for last_rx_timestamp == current_rx_timestamp,
for all UEs and eNBs.

When it's done, it increases current_rx_timestamp by samples_per_tti,
to inform UEs and eNBs that a new TTI is ready.

In the functions [UE|eNB]_trx_read, we wait for a new TTI to be ready,
that is we wait for current_rx_timestamp != last_rx_timestamp.

The UE has also to wait for processing threads to be done.
In the eNB it's not necessary because the processing is all
done in one thread, that is: read subframe, process this subframe,
emit subframe+4, and then back to read subframe.

The code is not clean. We should not use usleep but semaphores.

Also, do_[DL|UL]_sig should not read from rxdata and write to txdata,
but use internal buffers.

The functions [UE|eNB]_trx_read should call do_[DL|UL]_sig and then
copy from the internal buffers of the channel simulator into rxdata.

The functions [UE|eNB]_trx_write should write data passed into the
internal buffers of the channel simulator.

This reverts commit ce14050b, reversing
changes made to 0ada1e9e.

Not sure if this is the right thing to do, but it seems to be.

"start_eNB = 1;" is also necessary when the l2l1 task gets INITIALIZE_MESSAGE
otherwise the eNB does not start.

As it is today, I don't think oaisim will work with more than one eNB.

It's now done in lte-enb.c, even for oaisim.

It was probably the result of a bad merge.

At this point eNB_inst is not valid. Plus the T_ENB_MASTER_TICK
is now handled in lte-enb.c, even for oaisim.

oaisim is not functional with several UEs.
This fixes one issue. (It's still not functional for other reasons.)

We should use ENABLE_USE_MME, not USE_MME.
This code is useless anyway (I think, not sure, that's why I
leave it here), because the other threads wait for 'sync_var'
to become >=0.

Conflicts:
	openair1/PHY/INIT/lte_init.c
	openair1/PHY/LTE_TRANSPORT/dlsch_modulation.c
	openair1/PHY/LTE_TRANSPORT/power_control.c

The abstraction mode of oaisim does not work for the moment, it's better
to exit than to crash somewhere randomly.