Don't use gcc verbatim

it might have a different name
1 job for master in 1 minute and 34 seconds (queued for 1 second)
Status Job ID Name Coverage
  Test
failed #171194
x86_64-linux
validate

00:01:34

 
Name Stage Failure
failed
validate Test There has been a runner system failure, please try again
Running with gitlab-runner 11.10.1 (1f513601)
on ghc-ci-gce-x86_64-1 4vD1x1BB
Using Docker executor with image registry.gitlab.haskell.org/ghc/ci-images/x86_64-linux-deb9:2b69e99de97bd5bf1fbdbf45852231c3dcb602b6 ...
Pulling docker image registry.gitlab.haskell.org/ghc/ci-images/x86_64-linux-deb9:2b69e99de97bd5bf1fbdbf45852231c3dcb602b6 ...
Using docker image sha256:ea1a8b72741dad1e14d96ff587ddd038b8c0d105f50bdd22bf8dc8825a785ff5 for registry.gitlab.haskell.org/ghc/ci-images/x86_64-linux-deb9:2b69e99de97bd5bf1fbdbf45852231c3dcb602b6 ...
ERROR: Job failed (system failure): Error response from daemon: No such container: 24b0caadcfc698a67636679eb5a1d9ace79abfa7d531a0d889ce919c390b7487 (executor_docker.go:933:0s)