make --merge accept absolute paths

Summary: Latest Buck emits absolute paths in infer_deps.txt.

Reviewed By: akotulski

Differential Revision: D3528214

fbshipit-source-id: 5ca9466

infer/src/backend/mergeCapture.ml

@@ -152,7 +152,10 @@ let process_merge_file deps_file =
   let process_line line =
     match Str.split_delim (Str.regexp (Str.quote "\t")) line with
     | target :: _ :: target_results_dir :: _ ->
-        let infer_out_src = Filename.concat (Filename.dirname (buck_out ())) target_results_dir in
+        let infer_out_src =
+          if Filename.is_relative target_results_dir then
+            Filename.dirname (buck_out ()) // target_results_dir
+          else target_results_dir in
         let skiplevels = 2 in (** Don't link toplevel files, definitely not .start *)
         if should_link ~target ~target_results_dir ~stats infer_out_src infer_out_dst
         then slink ~stats ~skiplevels infer_out_src infer_out_dst