Remove the distinction between [Def] and [Defun].

There was no strong reason for this distinction to exist.

src/cppo_eval.ml

@@ -556,19 +556,12 @@ and expand_node ?(top = false) g env0 (x : node) =
         env
 
 
-    | `Def (loc, name, body)->
+    | `Def (loc, name, formals, body)->
         g.require_location := true;
         if M.mem name env0 then
           error loc (sprintf "%S is already defined" name)
         else
-          M.add name (EDef (loc, [], body, env0)) env0
-
-    | `Defun (loc, name, arg_names, body) ->
-        g.require_location := true;
-        if M.mem name env0 then
-          error loc (sprintf "%S is already defined" name)
-        else
-          M.add name (EDef (loc, arg_names, body, env0)) env0
+          M.add name (EDef (loc, formals, body, env0)) env0
 
     | `Undef (loc, name) ->
         g.require_location := true;

src/cppo_parser.mly

@@ -102,11 +102,12 @@ node:
 
                   let body = $2 @ [safe_space] in
                   let _, pos2 = $3 in
-                  `Def ((pos1, pos2), name, body) }
+                  let formals = [] in
+                  `Def ((pos1, pos2), name, formals, body) }
 
 | DEFUN def_args1 CL_PAREN unode_list0 ENDEF
                 { let (pos1, _), name = $1 in
-                  let args = $2 in
+                  let formals = $2 in
 
                   (* Additional spacing is needed for cases like 'foo()bar'
                      where 'foo()' expands into 'abc', giving 'abcbar'
@@ -117,7 +118,7 @@ node:
 
                   let body = $4 @ [safe_space] in
                   let _, pos2 = $5 in
-                  `Defun ((pos1, pos2), name, args, body) }
+                  `Def ((pos1, pos2), name, formals, body) }
 
 | DEFUN CL_PAREN
                 { error (fst (fst $1), snd $2)

src/cppo_types.ml

@@ -51,10 +51,11 @@ and arith_expr = (* signed int64 *)
 
 type node =
     [ `Ident of (loc * string * actuals)
-    | `Def of (loc * macro * body)
-    | `Defun of (loc * macro * formals * body)
          (* the list [actuals] is empty if and only if no parentheses
             are used at this macro invocation site. *)
+    | `Def of (loc * macro * formals * body)
+         (* the list [formals] is empty if and only if no parentheses
+            are used at this macro definition site. *)
     | `Undef of (loc * macro)
     | `Include of (loc * string)
     | `Ext of (loc * string * string)

src/cppo_types.mli

@@ -49,8 +49,9 @@ type node =
     [ `Ident of (loc * string * actuals)
          (* the list [actuals] is empty if and only if no parentheses
             are used at this macro invocation site. *)
-    | `Def of (loc * macro * body)
-    | `Defun of (loc * macro * formals * body)
+    | `Def of (loc * macro * formals * body)
+         (* the list [formals] is empty if and only if no parentheses
+            are used at this macro definition site. *)
     | `Undef of (loc * macro)
     | `Include of (loc * string)
     | `Ext of (loc * string * string)