- 'busy' has to be handled in a more atomic fashion to avoid crazy
  runtime race conditions
- the basic simulator is too fast sometimes; rewrite the accesses to
  the T cache to avoid there again crazy behaviors

Hopefully that's better...

This commit removes the warning:
make[4]: warning: jobserver unavailable: using -j1.  Add '+' to parent make rule.

Basically, inside a Makefile we should use $(MAKE) instead of make.

Since VCD has now to go through the T tracer, we enforce the consistency
of data found in common/utils/LOG/vcd_signal_dumper.[ch] with data
found in common/utils/T/T_messages.txt.

We might get completely rid of common/utils/LOG/vcd_signal_dumper.[ch] at some
point. For the moment, let's keep it.

This commit adds the program common/utils/T/check_vcd.c and necessary
modifications to enforce its use at compilation time.

If you modify common/utils/LOG/vcd_signal_dumper.[ch] but do not update
common/utils/T/T_messages.txt an error will pop up when you compile the
software. You have to keep both modules synchronized.

Use "error:" as prefix to error messages in genids.c
to help looking for errors in case of failure of
the build.

Don't use shm anymore. Use mmap directly.

Check result of send_is_on and close connection to tracee on error.

Make it compatible with 'template' gtwave files as found in openair's
repository.

The type VCD_NAME was added to the VCD IDs in T_messages.txt.
The database processing code was adapted to use it.
The tracer to_vcd was adapted to use it and render the produced vcd
output compatible with the 'template' gtkwave files.

When running to_vcd, do not forget to pass -vcd to use this feature.

This tracer allows the connection of several tracers to one tracee.

To use the multi tracer:
- run the tracee as usual, eg. ./lte-softmodem -O xxxx.conf --T_stdout 0
- run the multi tracer: ./multi -d ../T_messages.txt
- connect other tracers to the multi tracer:
   - ./enb -d ../T_messages.txt -p 2022
   - ./textlog -d ../T_messages.txt -p 2022
   - etc.

By default the multi tracer connects to the tracee to the port 2021,
as for any other tracer.

Then it accepts connections from other tracers on the port 2022.

This can be changed with parameters on the command line.

The tracee and the other tracers can be stopped/started at any time.

- bug fixed in ue and enb tracer: the socket needs to be closed
  in case of restart
- cleanup: fix spacing in T_messages.txt

Pass the command line arguemnt -vcd to trace all VCD variables
and functions.

- install package 'vim-common' to have 'xxd' needed by the compilation
  process of the T tracer
- change the way xxd is called so that no file is created in case
  of error

remove compilation warnings, especially when disabling T_TRACER. enhance LOG_M macro implementation, introduce LOG_DEBUG_XXX macro to replace #ifdef DEBUG_XXX

log.c simplification, fix usefull functionality which never worked, move all log code from openair2 to common

2. minor modifications in dlsch_demodulation.c for 2 eNB TX antennas, 1 RX antenna. Inconsistant indexing of some arrays in this case.
3. change in config_load_configmodule.c : removed exit(-1) when no configuration file is used. This makes unitary simulators exit. Effect on lte-XXsoftmodem TBC.

This was used for the ITTI analyzer.

The ITTI analyzer is now to be considered obsolete.
The source code will be removed at some point.

Log review step 1: legacy VCD removal, LOG macro modified, TTracer enabled at build time by default, in a way it, by default configuration,  provides console logs, as in previous versions

T tracer configuration identical for all executables, no ref to T Tracer config variables (T_port, T_wait...) outside the T tracer

Remove compilation warnings, also fix telnet server compilation failure and NB-IoT shared lib compilation failure introduced when reviewing L1 sources  organization

Whenever the value T_BUFFER_MAX changes, the tracers had to
be recompiled. The only reason why it was needed is because we
used some fixed size buffers to read events. This commit removes
this restriction.

Also, with the basic simulator, this value T_BUFFER_MAX now comes
with an #ifdef which would have required some special hackish-level
tricks in the tracers, which is not good.

Let's just allocate memory when needed.

This commit introduces a 'basic simulator'.

This basic simulator is made of:
- the standard eNB code using a special driver that mimics the USRP driver
- the standard UE code using a special driver that mimics the USRP driver
- no channel simulation
- some special code to deal with faster-than-realtime behaviour of this
  basic simulator

It connects one UE to one eNB. It requires an EPC, populated with the
correct configuration for the UE.

This is the initial release and may contain bugs (most probably race
conditions due to the faster-than-realtime behaviour).

To use it, see the documentation at:
    targets/ARCH/tcp_bridge/README.tcp_bridge_oai.

It has been tested with 25, 50 and 100 RBs, FDD mode.
(No check at all has been done to know if it could work in TDD mode.)

That allows to run several programs using this mechanism on the
same computer (say both eNB and UE, to debug).

(cherry picked from commit 3432385280c3155ee63a54be7c2e4846a17299de)

# Conflicts:
#	openair2/UTIL/LOG/log.c