Install system packages required by OCaml in the ocaml stage

Different releases of OCaml require different system libraries: libX11
isn't needed since 4.09, when the Graphics library was moved from the
core distribution to a separate package. On the opposite side, OCaml
5.1 can optionally use libzstd for compressing marshalled
data. Install these packages accordingly in the ocaml image.

src-opam/linux.ml

@@ -45,12 +45,19 @@ module RPM = struct
     let install = ksprintf (run "yum install -y %s") in
     update
     @@ install
-         "sudo passwd bzip2 patch rsync nano gcc-c++ git tar curl xz \
-          libX11-devel which m4 diffutils findutils%s"
+         "sudo passwd bzip2 patch rsync nano gcc-c++ git tar curl xz which m4 \
+          diffutils findutils%s"
          (match extra with None -> "" | Some x -> " " ^ x)
     @@ groupinstall "\"Development Tools\""
     |> crunch
 
+  let ocaml_dev_packages v =
+    if Ocaml_version.compare v Ocaml_version.Releases.v4_08 <= 0 then
+      Some "libX11-devel"
+    else if Ocaml_version.compare v Ocaml_version.Releases.v5_1_0 >= 0 then
+      Some "zstd"
+    else None
+
   let add_user ?uid ?gid ?(sudo = false) username =
     let uid = match uid with Some u -> sprintf "-u %d " u | None -> "" in
     let gid = match gid with Some g -> sprintf "-g %d " g | None -> "" in
@@ -93,11 +100,16 @@ module Apt = struct
     copy_heredoc
       ~src:[ heredoc ~strip:true "\tAcquire::Retries \"5\";" ]
       ~dst:"/etc/apt/apt.conf.d/mirror-retry" ()
-    @@ install
-         "build-essential curl git rsync sudo unzip nano libcap-dev \
-          libx11-dev%s"
+    @@ install "build-essential curl git rsync sudo unzip nano libcap-dev %s"
          (match extra with None -> "" | Some x -> " " ^ x)
 
+  let ocaml_dev_packages v =
+    if Ocaml_version.compare v Ocaml_version.Releases.v4_08 <= 0 then
+      Some "libX11-dev"
+    else if Ocaml_version.compare v Ocaml_version.Releases.v5_1_0 >= 0 then
+      Some "libzstd-dev"
+    else None
+
   let add_user ?uid ?gid ?(sudo = false) username =
     let uid = match uid with Some u -> sprintf "--uid %d " u | None -> "" in
     let gid = match gid with Some g -> sprintf "--gid %d " g | None -> "" in
@@ -134,10 +146,17 @@ module Apk = struct
 
   let dev_packages ?extra () =
     install
-      "build-base patch tar ca-certificates git rsync curl sudo bash \
-       libx11-dev nano coreutils xz ncurses-dev%s"
+      "build-base patch tar ca-certificates git rsync curl sudo bash nano \
+       coreutils xz ncurses-dev%s"
       (match extra with None -> "" | Some x -> " " ^ x)
 
+  let ocaml_dev_packages v =
+    if Ocaml_version.compare v Ocaml_version.Releases.v4_08 <= 0 then
+      Some "libX11-dev"
+    else if Ocaml_version.compare v Ocaml_version.Releases.v5_1_0 >= 0 then
+      Some "zstd"
+    else None
+
   let add_user ?uid ?gid ?(sudo = false) username =
     let home = "/home/" ^ username in
     (match gid with
@@ -197,12 +216,18 @@ module Zypper = struct
     update
     @@ install "-t pattern devel_C_C++"
     @@ install
-         "sudo git unzip curl gcc-c++ libcap-devel xz libX11-devel bzip2 which \
-          rsync gzip%s"
+         "sudo git unzip curl gcc-c++ libcap-devel xz bzip2 which rsync gzip%s"
          (match extra with None -> "" | Some x -> " " ^ x)
     @@ run "zypper clean --all"
     |> crunch
 
+  let ocaml_dev_packages v =
+    if Ocaml_version.compare v Ocaml_version.Releases.v4_08 <= 0 then
+      Some "libX11-devel"
+    else if Ocaml_version.compare v Ocaml_version.Releases.v5_1_0 >= 0 then
+      Some "zstd"
+    else None
+
   let add_user ?uid ?gid ?(sudo = false) username =
     let home = "/home/" ^ username in
     run "useradd %s%s -d %s -m --user-group %s"
@@ -233,10 +258,17 @@ module Pacman = struct
 
   let dev_packages ?extra () =
     install
-      "make gcc patch tar ca-certificates git rsync curl sudo bash libx11 nano \
+      "make gcc patch tar ca-certificates git rsync curl sudo bash nano \
        coreutils xz ncurses diffutils unzip%s"
       (match extra with None -> "" | Some x -> " " ^ x)
 
+  let ocaml_dev_packages v =
+    if Ocaml_version.compare v Ocaml_version.Releases.v4_08 <= 0 then
+      Some "libx11"
+    else if Ocaml_version.compare v Ocaml_version.Releases.v5_1_0 >= 0 then
+      Some "zstd"
+    else None
+
   let add_user ?uid ?gid ?(sudo = false) username =
     let home = "/home/" ^ username in
     run "useradd %s%s -d %s -m --user-group %s"

src-opam/linux.mli

@@ -48,6 +48,10 @@ module RPM : sig
   (** [dev_packages ?extra ()] will install the base development tools and [sudo],
       [passwd] and [git].  Extra packages may also be optionally supplied via [extra]. *)
 
+  val ocaml_dev_packages : Ocaml_version.t -> string option
+  (** [ocaml_dev_packages v] returns packages that are required by the
+      OCaml distribution at version [v]. *)
+
   val install_system_ocaml : t
   (** Install the system OCaml packages via Yum *)
 end
@@ -69,6 +73,10 @@ module Apt : sig
   (** [dev_packages ?extra ()] will install the base development tools and [sudo],
       [passwd] and [git] and X11.  Extra packages may also be optionally supplied via [extra]. *)
 
+  val ocaml_dev_packages : Ocaml_version.t -> string option
+  (** [ocaml_dev_packages v] returns packages that are required by the
+      OCaml distribution at version [v]. *)
+
   val install_system_ocaml : t
   (** Install the system OCaml packages via [apt-get] *)
 end
@@ -85,6 +93,10 @@ module Apk : sig
   (** [dev_packages ?extra ()] will install the base development tools and [sudo],
       [passwd] and [git].  Extra packages may also be optionally supplied via [extra]. *)
 
+  val ocaml_dev_packages : Ocaml_version.t -> string option
+  (** [ocaml_dev_packages v] returns packages that are required by the
+      OCaml distribution at version [v]. *)
+
   val add_user : ?uid:int -> ?gid:int -> ?sudo:bool -> string -> t
   (** [add_user username] will install a new user with name [username] and a locked
       password.  If [sudo] is true then root access with no password will also be
@@ -117,6 +129,10 @@ module Zypper : sig
   (** [dev_packages ?extra ()] will install the base development tools and [sudo],
       [passwd] and [git].  Extra packages may also be optionally supplied via [extra]. *)
 
+  val ocaml_dev_packages : Ocaml_version.t -> string option
+  (** [ocaml_dev_packages v] returns packages that are required by the
+      OCaml distribution at version [v]. *)
+
   val install_system_ocaml : t
   (** Install the system OCaml packages via [zypper] *)
 end
@@ -138,6 +154,10 @@ module Pacman : sig
   (** [dev_packages ?extra ()] will install the base development tools and [sudo],
       [passwd] and [git].  Extra packages may also be optionally supplied via [extra]. *)
 
+  val ocaml_dev_packages : Ocaml_version.t -> string option
+  (** [ocaml_dev_packages v] returns packages that are required by the
+      OCaml distribution at version [v]. *)
+
   val install_system_ocaml : t
   (** Install the system OCaml packages via [pacman] *)
 end

src-opam/opam.ml

@@ -496,6 +496,27 @@ let gen_opam2_distro ?win10_revision ?winget ?(clone_opam_repo = true) ?arch
   in
   (D.tag_of_distro d, fn @@ clone @@ pers)
 
+let ocaml_dev_packages distro v =
+  let open Linux in
+  match D.package_manager distro with
+  | `Apk ->
+      Option.fold ~none:empty ~some:(Apk.install "%s")
+        (Apk.ocaml_dev_packages v)
+  | `Apt ->
+      Option.fold ~none:empty ~some:(Apt.install "%s")
+        (Apt.ocaml_dev_packages v)
+  | `Yum ->
+      Option.fold ~none:empty ~some:(RPM.install "%s")
+        (RPM.ocaml_dev_packages v)
+  | `Zypper ->
+      Option.fold ~none:empty ~some:(Zypper.install "%s")
+        (Zypper.ocaml_dev_packages v)
+  | `Pacman ->
+      Option.fold ~none:empty ~some:(Pacman.install "%s")
+        (Pacman.ocaml_dev_packages v)
+  | `Windows -> empty
+  | `Cygwin -> empty
+
 let create_switch ~arch distro t =
   let create_switch switch pkg =
     run "opam switch create %s %s" (OV.to_string switch) pkg

src-opam/opam.mli

@@ -68,6 +68,11 @@ val gen_opam2_distro :
    will be build in an prepended build stage. If specified, then
    winget will be pulled from the [winget] external image. *)
 
+val ocaml_dev_packages : Distro.t -> Ocaml_version.t -> Dockerfile.t
+(** [ocaml_dev_packages distro version] returns packages that are
+    required under [distro] by the OCaml distribution at version
+    [version].  *)
+
 val all_ocaml_compilers :
   string -> Ocaml_version.arch -> Distro.t -> string * Dockerfile.t
 (** [all_ocaml_compilers hub_id arch distro] will generate an opam2