Bump dune.

dune-project

@@ -1,4 +1,4 @@
-(lang dune 2.8)
+(lang dune 3.6)
 (version 0.3.1)
 (name srt)
 (source (github savonet/ocaml-srt))

src/generator/dune

@@ -54,16 +54,24 @@
  (action
   (run ../config/discover.exe)))
 
+(rule
+ (targets ctypes_dir)
+ (action
+  (with-stdout-to
+   %{targets}
+   (run dirname %{lib:ctypes:ctypes_cstubs_internals.h}))))
+
 (rule
  (targets gen_types_c_target.exe)
  (deps
   (:c_flags ./c_flags)
+  (:ctypes_dir ./ctypes_dir)
   (:c_code ./gen_types.c))
  (action
   (run
    %{ocaml-config:c_compiler}
    -I
-   %{lib:ctypes:}
+   %{read-lines:ctypes_dir}
    -I
    %{ocaml-config:standard_library}
    %{read-lines:c_flags}
@@ -102,12 +110,13 @@
  (targets gen_constants_c_target.exe)
  (deps
   (:c_flags ./c_flags)
+  (:ctypes_dir ./ctypes_dir)
   (:c_code ./gen_constants.c))
  (action
   (run
    %{ocaml-config:c_compiler}
    -I
-   %{lib:ctypes:}
+   %{read-lines:ctypes_dir}
    -I
    %{ocaml-config:standard_library}
    %{read-lines:c_flags}

srt.opam

@@ -16,7 +16,7 @@ bug-reports: "https://github.com/savonet/ocaml-srt/issues"
 depends: [
   "conf-srt" {build}
   "conf-pkg-config" {build}
-  "dune" {>= "2.8"}
+  "dune" {>= "3.6"}
   "dune-configurator" {build}
   "ocamlfind"
   "ctypes"