Add Mac CI build config

5 jobs for master in 9 minutes and 41 seconds (queued for 5 seconds)
Status Job ID Name Coverage
  Build
failed #20700634
clang

00:03:12

passed #20700632
inkscape

00:09:41

failed #20700633
mac
inkscape:mac

 
  Test
skipped #20700635
test
 
  Deploy
skipped #20700636
allowed to fail manual
pages
 
Name Stage Failure
failed
clang Build There is an unknown failure, please try again
$ apt-get install -y clang-3.8 clang
Reading package lists...
Building dependency tree...
Reading state information...
E: Unable to locate package clang-3.8
E: Couldn't find any package by glob 'clang-3.8'
E: Couldn't find any package by regex 'clang-3.8'
E: Unable to locate package clang
ERROR: Job failed: exit code 1
failed
inkscape:mac Build There is an unknown failure, please try again
No job log