Automate abi compliance check

[bourtemb]

libzmq project has tried something to automate abi compliance checking process (recent travis builds are failing because of that though).
Maybe we could do something similar as what they did:
https://github.com/zeromq/libzmq/blob/02f7dca678095099be8774844fec693f390b2223/builds/abi-compliance-checker/ci_build.sh
https://github.com/zeromq/libzmq/blob/9bb6b2142385b78d47811b73745b9c21ec366106/.travis.yml#L136-L143

[t-b]

Here is the script I just made while reviewing a PR.

#!/usr/bin/env bash

set -e

new_revision=$(git rev-parse HEAD)
old_revision=$(git merge-base --fork-point tango-9-lts HEAD)

function print_abi_api_breakages() {
   echo "ABI breakages detected:"
   cat compat_reports/libtango/${old_revision}_to_${new_revision}/abi_affected.txt | c++filt
   echo "API breakages detected:"
   cat compat_reports/libtango/${old_revision}_to_${new_revision}/src_affected.txt | c++filt
   exit 1
}

# Generate info for new branch

git checkout ${new_revision} 
mkdir build-new
cd build-new
cmake -DCMAKE_BUILD_TYPE=Debug  ..
make
abi-dumper libtango.so -o libtango-new-${new_revision}.dump -lver ${new_revision}
cd ..

# Generate info for old branch

git checkout ${old_revision} 
mkdir build-old
cd build-old
cmake -DCMAKE_BUILD_TYPE=Debug  ..
make
abi-dumper libtango.so -o libtango-old-${old_revision}.dump -lver ${old_revision}
cd ..

# Compare results

abi-compliance-checker -l libtango -old build-old/libtango-old-${old_revision}.dump \
                                   -new build-new/libtango-new-${new_revision}.dump \
                                   -list-affected || print_abi_api_breakages