oasis patch that adds an .nobj.o target

[Anil Madhavapeddy <anil@xxxxxxxxxx>]

This patch against darcs-oasis is sufficient to add a "native output obj" 
target that outputs a standalone object file.  Just one more little rule 
required to do the Xen objcopy/link, but this will also be useful for kFreeBSD 
too.  This one is mainly for Dave as he's working on ocaml-xenstore atm.

I'll submit an upstreamable patch shortly and have a Xen plugin to OASIS that 
will make all our build pains waft away into a gentle summer breeze.

-anil

avsm@debian:~/src/darcs/oasis$ darcs diff
diff -rN -u old-oasis/src/plugins/ocamlbuild/MyOCamlbuildBase.ml 
new-oasis/src/plugins/ocamlbuild/MyOCamlbuildBase.ml
--- old-oasis/src/plugins/ocamlbuild/MyOCamlbuildBase.ml        2012-08-24 
18:45:09.249486856 +0100
+++ new-oasis/src/plugins/ocamlbuild/MyOCamlbuildBase.ml        2012-08-24 
18:45:09.301486856 +0100
@@ -165,6 +165,15 @@
             )
             t.lib_c;
 
+          (* Add output_obj rules mapped to .nobj.o *)
+          let native_output_obj x =
+            OC.link_gen "cmx" "cmxa" !Options.ext_lib [!Options.ext_obj; 
"cmi"] 
+              OC.ocamlopt_link_prog
+              (fun tags -> tags++"ocaml"++"link"++"byte"++"output_obj") x
+          in
+          rule "ocaml: cmx* and o* -> .nobj.o" ~prod:"%.nobj.o" 
~deps:["%.cmx"; "%.o"]
+            (native_output_obj "%.cmx" "%.nobj.o");
+
             (* Add flags *)
             List.iter
             (fun (tags, cond_specs) ->
diff -rN -u old-oasis/src/plugins/ocamlbuild/MyOCamlbuildFindlib.ml 
new-oasis/src/plugins/ocamlbuild/MyOCamlbuildFindlib.ml
--- old-oasis/src/plugins/ocamlbuild/MyOCamlbuildFindlib.ml     2012-08-24 
18:45:09.249486856 +0100
+++ new-oasis/src/plugins/ocamlbuild/MyOCamlbuildFindlib.ml     2012-08-24 
18:45:09.301486856 +0100
@@ -86,6 +86,7 @@
         
         (* When one link an OCaml library/binary/package, one should use 
-linkpkg *)
         flag ["ocaml"; "link"; "program"] & A"-linkpkg";
+        flag ["ocaml"; "link"; "output_obj"] & A"-linkpkg";
         
         (* For each ocamlfind package one inject the -package option when
          * compiling, computing dependencies, generating documentation and
diff -rN -u old-oasis/src/plugins/ocamlbuild/OCamlbuildPlugin.ml 
new-oasis/src/plugins/ocamlbuild/OCamlbuildPlugin.ml
--- old-oasis/src/plugins/ocamlbuild/OCamlbuildPlugin.ml        2012-08-24 
18:45:09.249486856 +0100
+++ new-oasis/src/plugins/ocamlbuild/OCamlbuildPlugin.ml        2012-08-24 
18:45:09.301486856 +0100
@@ -158,9 +158,9 @@
                  let acc =
                    match bs.bs_compiled_object with
                      | Native ->
-                         (target ".native") :: acc
+                         (target ".native") :: (target ".nobj.o") ::  acc
                      | Best when bool_of_string (is_native ()) ->
-                         (target ".native") :: acc
+                         (target ".native") :: (target ".nobj.o") :: acc
                      | Byte
                      | Best ->
                          (target ".byte") :: acc
@@ -928,11 +928,11 @@
                    let ext =
                      match bs.bs_compiled_object with
                        | Best ->
-                           "{native,byte}"
+                           "{native,byte,nobj.o}"
                        | Byte ->
                            "byte"
                        | Native ->
-                           "native"
+                           "native,nobj.o"
                    in
                      prepend_bs_path bs
                        (OASISUnixPath.replace_extension