[camlp4] add YaM.is_file_empty

git-svn-id: http://caml.inria.fr/svn/ocaml/trunk@7583 f963ae5c-01c2-4b8c-9fe0-0dff7051ff02

camlp4/build/YaM.ml

@@ -880,3 +880,9 @@ let scall cmd =
   let str = input_line cin in str
 
 let which x = scall ("which"^^x)
+
+let is_file_empty f =
+  let i = open_in f in
+  let res = in_channel_length i < 1 in
+  close_in i; res
+

camlp4/build/YaM.mli

@@ -302,3 +302,5 @@ val best: (string * string) list -> string
 val getenv: string -> string -> string
 
 val which : string -> string
+
+val is_file_empty : string -> bool