Add m4 dependency to most jobs

.gitlab-ci.yml

@@ -6,7 +6,7 @@ stages:
 
 # OCaml version 4.02
 ocaml_402:
-  before_script: 
+  before_script:
     - sudo apk update && sudo apk add m4
   stage: test
   image: ocaml/opam:alpine_ocaml-4.02.3
@@ -15,6 +15,8 @@ ocaml_402:
 
 # OCaml version 4.00
 ocaml_400:
+  before_script:
+    - sudo apk update && sudo apk add m4
   stage: test
   image: ocaml/opam:alpine_ocaml-4.00.1
   script: "./gitlab-ci.sh"
@@ -22,6 +24,8 @@ ocaml_400:
 
 # OCaml version 4.01
 ocaml_401:
+  before_script:
+    - sudo apk update && sudo apk add m4
   stage: test
   image: ocaml/opam:alpine_ocaml-4.01.0
   script: "./gitlab-ci.sh"
@@ -29,6 +33,8 @@ ocaml_401:
 
 # OCaml version 4.03
 ocaml_403:
+  before_script:
+    - sudo apk update && sudo apk add m4
   stage: test
   image: ocaml/opam:alpine_ocaml-4.03.0
   script: "./gitlab-ci.sh"
@@ -36,6 +42,8 @@ ocaml_403:
 
 # OCaml version 4.03
 ocaml_403_flambda:
+  before_script:
+    - sudo apk update && sudo apk add m4
   stage: test
   image: ocaml/opam:alpine_ocaml-4.03.0_flambda
   script: "./gitlab-ci.sh"
@@ -43,6 +51,8 @@ ocaml_403_flambda:
 
 # ---------------
 ubuntu:
+  before_script:
+    - sudo apt-get update && sudo apt-get install m4
   stage: real
   image: ocaml/opam:ubuntu
   script: "export OC_NOTEST=true; ./gitlab-ci.sh system"
@@ -50,18 +60,24 @@ ubuntu:
 
 
 debian:
+  before_script:
+    - sudo apt-get update && sudo apt-get install m4
   stage: real
   image: ocaml/opam:debian
   script: "export OC_NOTEST=true; ./gitlab-ci.sh system"
   allow_failure: false
 
 centos:
+  before_script:
+    - sudo dnf install m4-devel
   stage: real
   image: ocaml/opam:centos
   script: "export OC_NOTEST=true; ./gitlab-ci.sh system"
   allow_failure: false
 
 fedora:
+  before_script:
+    - sudo dnf install m4-devel
   stage: real
   image: ocaml/opam:fedora
   script: "export OC_NOTEST=true; ./gitlab-ci.sh system"