Add Gitlab CI

This includes test to compile project, to run tests in various
environments and code coverage.
6 jobs for master in 1 minute and 37 seconds (queued for 1 second)
Status Job ID Name Coverage
  Build
passed #434326
build

00:00:28

passed #434327
dist

00:00:29

 
  Test
passed #434328
check

00:00:30

failed #434330
allowed to fail
lint

00:00:27

passed #434329
valgrind

00:00:58

 
  Coverage
passed #434331
coverage

00:00:31

90.7%
 
Name Stage Failure
failed
lint Test
3/5 files checked 84% done
Checking logc_assert.h ...
Checking logc_assert.h: DEFLOG...
4/5 files checked 89% done
Checking logc_util.h ...
Checking logc_util.h: DEFLOG...
5/5 files checked 100% done
make: *** [Makefile:1496: lint] Error 1
ERROR: Job failed: exit code 1