Use make as a build system for opam files.

There are now two opam files:
- unison.opam is the main opam file. It has an optional dependency to
  lablgtk3, so that the GUI is built only if the lablgtk3 package is installed.
- unison-gui.opam is a pseudo-package, with both unison and lablgtk3 as
  dependencies. It can be used to force the GUI to be installed.

As a side effect, remove the package information from the dune-project files,
to avoid redundancy.

dune-project

@@ -2,75 +2,4 @@
 
 (name unison)
 
-(version dev)
-
 (generate_opam_files false)
-
-(license GPL-3.0-or-later)
-
-(maintainers "[email protected]")
-
-(authors "Trevor Jim" "Benjamin C. Pierce" "J\195\169r\195\180me Vouillon")
-
-(source
- (github bcpierce00/unison))
-
-(homepage https://www.cis.upenn.edu/~bcpierce/unison/)
-
-(documentation "https://github.com/bcpierce00/unison/wiki")
-
-(package
- (name unison)
- (synopsis "File-synchronization tool for Unix and Windows")
- (description "\
-Text based user interface for Unison.
-
-Unison is a file-synchronization tool for Unix and Windows.
-It allows two replicas of a collection of files and directories
-to be stored on different hosts (or different disks on the same host),
-modified separately, and then brought up to date by propagating
-the changes in each replica to the other.
-")
- (depends
-  (ocaml
-   (>= 4.08))
-  (dune
-   (>= 2.3))))
-
-(package
- (name unison-gui)
- (synopsis "File-synchronization tool for Unix and Windows")
- (description "\
-Graphical user interface for Unison.
-
-Unison is a file-synchronization tool for Unix and Windows.
-It allows two replicas of a collection of files and directories
-to be stored on different hosts (or different disks on the same host),
-modified separately, and then brought up to date by propagating
-the changes in each replica to the other.
-")
- (depends
-  (ocaml
-   (>= 4.08))
-  (dune
-   (>= 2.3))
-  lablgtk))
-
-(package
- (name unison-fsmonitor)
- (synopsis "File-synchronization tool for Unix and Windows")
- (description "\
-This optional add-on for unison monitors file system changes
-on all given (relative to root) paths.
-
-Unison is a file-synchronization tool for Unix and Windows.
-It allows two replicas of a collection of files and directories
-to be stored on different hosts (or different disks on the same host),
-modified separately, and then brought up to date by propagating
-the changes in each replica to the other.
-")
- (depends
-  (ocaml
-   (>= 4.08))
-  (dune
-   (>= 2.3))))

src/dune

@@ -18,14 +18,14 @@
 (executable
  (name linktext)
  (public_name unison)
- (package unison)
+ (package unison) ; Dummy: we don't use packages
  (modules linktext)
  (libraries unison_lib))
 
 (executable
  (name linkgtk3)
  (public_name unison-gui)
- (package unison-gui)
+ (package unison-gui) ; Dummy: we don't use packages
  (flags :standard -w -3-6-9-27-32-52)
  (modules linkgtk3 uigtk3)
  (libraries threads unison_lib lablgtk3))

src/fsmonitor/inotify/dune

@@ -20,7 +20,7 @@
 (executable
  (name watcher)
  (public_name unison-fsmonitor)
- (package unison-fsmonitor)
+ (package unison) ; Dummy: we don't use packages
  (enabled_if
   (or
    (= %{system} "linux")

src/fsmonitor/solaris/dune

@@ -14,7 +14,7 @@
 (executable
  (name watcher)
  (public_name unison-fsmonitor)
- (package unison-fsmonitor)
+ (package unison) ; Dummy: we don't use packages
  (enabled_if (= %{system} "solaris"))
  (modules watcher)
  (flags :standard -w -27)

unison-gui.opam

@@ -0,0 +1,22 @@
+opam-version: "2.0"
+maintainer: "[email protected]"
+authors: [
+  "Trevor Jim"
+  "Benjamin C. Pierce"
+  "Jérôme Vouillon"
+]
+license: "GPL-3.0-or-later"
+homepage: "https://www.cis.upenn.edu/~bcpierce/unison/"
+bug-reports: "https://github.com/bcpierce00/unison/issues"
+dev-repo: "git://github.com/bcpierce00/unison.git"
+depends: [
+  "unison" {= version}
+  "lablgtk3"
+]
+synopsis: "Pseudo-package for Unison GUI"
+description: """
+Unison is a file-synchronization tool for Unix and Windows. It allows
+two replicas of a collection of files and directories to be stored on
+different hosts (or different disks on the same host), modified
+separately, and then brought up to date by propagating the changes in
+each replica to the other."""

unison.opam

@@ -9,10 +9,12 @@ license: "GPL-3.0-or-later"
 homepage: "https://www.cis.upenn.edu/~bcpierce/unison/"
 bug-reports: "https://github.com/bcpierce00/unison/issues"
 dev-repo: "git://github.com/bcpierce00/unison.git"
-build: ["dune" "build" "-p" name "-j" jobs]
+build: [make "-j" jobs]
+install: [make "PREFIX=%{prefix}%" "install"]
 depends: [
   "ocaml" {>= "4.08"}
-  "dune" {>= "2.3"}
+]
+depopts: [
   "lablgtk3" {>= "3.1.0"}
 ]
 synopsis: "File-synchronization tool for Unix and Windows"