add support for gitlab-ci

* .gitlab-ci.yml: here.
2 jobs for master in 3 minutes and 10 seconds (queued for 6 minutes and 50 seconds)
Status Job ID Name Coverage
  Test
failed #1638
debian-stable-gcc

00:03:10

failed #1637
debian-stable-gcc

00:04:50

 
Name Stage Failure
failed
debian-stable-gcc Test
src/task/Makefile.am:1:   If 'LT_INIT' is in 'configure.ac', make sure
src/task/Makefile.am:1: its definition is in aclocal's search path.
src/vm/Makefile.am:1: error: Libtool library used but 'LIBTOOL' is undefined
src/vm/Makefile.am:1: The usual way to define 'LIBTOOL' is to add 'LT_INIT'
src/vm/Makefile.am:1: to 'configure.ac' and run 'aclocal' and 'autoconf' again.
src/vm/Makefile.am:1: If 'LT_INIT' is in 'configure.ac', make sure
src/vm/Makefile.am:1: its definition is in aclocal's search path.
autoreconf: automake failed with exit status: 1
ERROR: Job failed: exit code 1