I've got linphonec working on a vanilla (freshly installed and unmodified) raspian.
Version 3.6.1 [of linphonec] is widely known to have issues;
but which is specifically causing the error, I don't know.
What I do know, is that the version which currently gets installed from apt (as of Aug 4, 2018) is a few versions behind the current version, which is 3.12.0.
What worked for me is building the project from source.
This is easier than you might think. Caveat: You'll need about two gigabyte free space. Let's get it done:
Start with installing so called build-dependencies:
sudo apt-get install cmake automake autoconf libtool intltool yasm libasound2-dev libpulse-dev libv4l-dev nasm git libglew-dev
The following step may take some time (~30m) as the project is huge.
In your home directory call the following, in order to retrieve the sourcecode:
git clone git://git.linphone.org/linphone-desktop.git --recursive
change into the now created directory:
cd linphone-desktop
the following step is optional, read carefully:
I run my RPi in "headless" mode; i.e. do not have a graphical desktop environment running on my pi.
Therefore it would be a waste of time to compile all the gui-tools of linphone.
So, if you do not need gui, like me;
run the following line:
./prepare.py no-ui -DENABLE_OPENH264=ON -DENABLE_WEBRTC_AEC=OFF -DENABLE_UNIT_TESTS=OFF -DENABLE_MKV=OFF -DENABLE_FFMPEG=ON -DENABLE_CXX_WRAPPER=OFF -DENABLE_NON_FREE_CODECS=ON -DENABLE_VCARD=OFF -DENABLE_BV16=OFF -DENABLE_V4L=OFF
Whether you decided to use the line above or not,
the last step is to build the project using make.
Make usually runs on one core of your processor and does therefore potentially waste your time.
Make has a flag called '-j' which allows users to specify how many jobs should be done at once. Knowing your system now pays dividends!
As I'm building on an pi3 revision b, my processor is a quad-core ARM Cortex-A53.
What matters is the quadcore part.
So call the following:
make -j4
This step should also take about 30 minutes if you decided to omit the job flag.
So we're done.
The compiled output lies now in the subdirectory OUTPUT/no-ui/bin.
You may call the linphonec binary like this, for example:
cd OUTPUT/no-ui/bin
and then
./linphonec -v
and get a result like this:
version: 3.12.0
if you call the tool without the version flag, it runs as you specified it to do in ~/.linphonerc (in your/pi's home directory).