filename: add a make temporary file function

Author: rjbou

src/core/opamFilename.ml

@@ -261,6 +261,9 @@ let exists filename =
 let opt_file filename =
   if exists filename then Some filename else None
 
+let mk_tmp_file () =
+  of_string @@ OpamSystem.mk_temp_dir ()
+
 let with_tmp_file fn =
   OpamSystem.with_tmp_file (fun file -> fn (of_string file))
 

src/core/opamFilename.mli

@@ -177,6 +177,10 @@ val exists: t -> bool
     a symlink to one *)
 val opt_file: t -> t option
 
+(** Returns an unique filename in temporary directory.
+    If it exists, cleaned at exit *)
+val mk_tmp_file:  unit -> t
+
 (** Execute a function with a file in a temp directory.
     It is always cleaned up afterwards. *)
 val with_tmp_file: (t -> 'a) -> 'a