diff --git a/Changes b/Changes
index 21177e4..3b15908 100644
--- a/Changes
+++ b/Changes
@@ -88,6 +88,11 @@ OCamlbuild:
   (Peter Zotov)
 - PR#6720: pass -g to C compilers when tag 'debug' is set
   (Peter Zotov, Gabriel Scherer)
+- PR#6733: add .byte.so and .native.so targets to pass
+  -output-obj -cclib -shared.
+  (Peter Zotov)
+- PR#6733: "runtime_variant(X)" to pass -runtime-variant X option.
+  (Peter Zotov)

 Tools:
 - PR#6641: add -g, -ocamlcflags, -ocamloptflags options to ocamlmklib
diff --git a/ocamlbuild/ocaml_compiler.ml b/ocamlbuild/ocaml_compiler.ml
index c270a7f..7526598 100644
--- a/ocamlbuild/ocaml_compiler.ml
+++ b/ocamlbuild/ocaml_compiler.ml
@@ -156,7 +156,7 @@ let byte_compile_ocaml_interf mli cmi env build =
 let compile_ocaml_interf mli cmi env build =
   let mli = env mli and cmi = env cmi in
   prepare_compile build mli;
-  let tags = tags_of_pathname mli++"interf" in
+  let tags = tags_of_pathname mli++"interf" in
   let comp_c = if Tags.mem "native" tags then ocamlopt_c else ocamlc_c in
   comp_c tags mli cmi

@@ -266,6 +266,9 @@ let byte_link = byte_link_gen ocamlc_link_prog
 let byte_output_obj = byte_link_gen ocamlc_link_prog
   (fun tags -> tags++"ocaml"++"link"++"byte"++"output_obj")

+let byte_output_shared = byte_link_gen ocamlc_link_prog
+  (fun tags -> tags++"ocaml"++"link"++"byte"++"output_obj"++"output_shared")
+
 let byte_library_link = byte_link_gen byte_lib_linker byte_lib_linker_tags

 let byte_debug_link_gen =
@@ -286,6 +289,9 @@ let native_link x = native_link_gen ocamlopt_link_prog
 let native_output_obj x = native_link_gen ocamlopt_link_prog
   (fun tags -> tags++"ocaml"++"link"++"native"++"output_obj") x

+let native_output_shared x = native_link_gen ocamlopt_link_prog
+  (fun tags -> tags++"ocaml"++"link"++"native"++"output_obj"++"output_shared") x
+
 let native_library_link x =
   native_link_gen native_lib_linker native_lib_linker_tags x

diff --git a/ocamlbuild/ocaml_compiler.mli b/ocamlbuild/ocaml_compiler.mli
index 38206e5..0c951ab 100644
--- a/ocamlbuild/ocaml_compiler.mli
+++ b/ocamlbuild/ocaml_compiler.mli
@@ -43,11 +43,13 @@ val link_gen :
   string -> string -> Rule.action
 val byte_link : string -> string -> Rule.action
 val byte_output_obj : string -> string -> Rule.action
+val byte_output_shared : string -> string -> Rule.action
 val byte_library_link : string -> string -> Rule.action
 val byte_debug_link : string -> string -> Rule.action
 val byte_debug_library_link : string -> string -> Rule.action
 val native_link : string -> string -> Rule.action
 val native_output_obj : string -> string -> Rule.action
+val native_output_shared : string -> string -> Rule.action
 val native_library_link : string -> string -> Rule.action
 val native_shared_library_link : ?tags:(string list) -> string -> string -> Rule.action
 val native_profile_link : string -> string -> Rule.action
diff --git a/ocamlbuild/ocaml_specific.ml b/ocamlbuild/ocaml_specific.ml
index 3162850..99c38a7 100644
--- a/ocamlbuild/ocaml_specific.ml
+++ b/ocamlbuild/ocaml_specific.ml
@@ -61,7 +61,9 @@ let x_p_dll = "%.p"-.-ext_dll;;
 (* -output-obj targets *)
 let x_byte_c = "%.byte.c";;
 let x_byte_o = "%.byte"-.-ext_obj;;
+let x_byte_so = "%.byte"-.-ext_dll;;
 let x_native_o = "%.native"-.-ext_obj;;
+let x_native_so = "%.native"-.-ext_dll;;

 rule "target files"
   ~dep:"%.itarget"
@@ -221,6 +223,15 @@ rule "ocaml: cmo* -> byte.c"
   ~dep:"%.cmo"
   (Ocaml_compiler.byte_output_obj "%.cmo" x_byte_c);;

+rule "ocaml: cmo* -> byte.(so|dll|dylib)"
+  ~prod:x_byte_so
+  ~dep:"%.cmo"
+  ~doc:"The foo.byte.so target, or foo.byte.dll under Windows, \
+  or foo.byte.dylib under Mac OS X will produce a shared library file
+  by passing the -output-obj and -cclib -shared options \
+  to the OCaml compiler. See also foo.native.{so,dll,dylib}."
+  (Ocaml_compiler.byte_output_shared "%.cmo" x_byte_so);;
+
 rule "ocaml: p.cmx* & p.o* -> p.native"
   ~prod:"%.p.native"
   ~deps:["%.p.cmx"; x_p_o]
@@ -239,6 +250,11 @@ rule "ocaml: cmx* & o* -> native.(o|obj)"
   ~deps:["%.cmx"; x_o]
   (Ocaml_compiler.native_output_obj "%.cmx" x_native_o);;

+rule "ocaml: cmx* & o* -> native.(so|dll|dylib)"
+  ~prod:x_native_so
+  ~deps:["%.cmx"; x_o]
+  (Ocaml_compiler.native_output_shared "%.cmx" x_native_so);;
+
 rule "ocaml: mllib & d.cmo* -> d.cma"
   ~prod:"%.d.cma"
   ~dep:"%.mllib"
@@ -624,6 +640,8 @@ let () =
     (fun param -> S [A "-open"; A param]);
   pflag ["ocaml"; "compile"] "open"
     (fun param -> S [A "-open"; A param]);
+  pflag ["ocaml"; "link"] "runtime_variant"
+    (fun param -> S [A "-runtime-variant"; A param]);
   ()

 let camlp4_flags camlp4s =
@@ -678,6 +696,7 @@ flag ["c";     "debug"; "compile"] (A "-g");
 flag ["c";     "debug"; "link"] (A "-g");
 flag ["ocaml"; "link"; "native"; "output_obj"] (A"-output-obj");;
 flag ["ocaml"; "link"; "byte"; "output_obj"] (A"-output-obj");;
+flag ["ocaml"; "link"; "output_shared"] & (S[A"-cclib"; A"-shared"]);;
 flag ["ocaml"; "dtypes"; "compile"] (A "-dtypes");;
 flag ["ocaml"; "annot"; "compile"] (A "-annot");;
 flag ["ocaml"; "annot"; "pack"] (A "-annot");;
diff --git a/ocamlbuild/testsuite/internal.ml b/ocamlbuild/testsuite/internal.ml
index d02946b..b669851 100644
--- a/ocamlbuild/testsuite/internal.ml
+++ b/ocamlbuild/testsuite/internal.ml
@@ -160,6 +160,13 @@ let () = test "OutputObj"
   ~tree:[T.f "hello.ml" ~content:"print_endline \"Hello, World!\""]
   ~targets:("hello.byte.o",["hello.byte.c";"hello.native.o"]) ();;

+let () = test "OutputShared"
+  ~options:[`no_ocamlfind]
+  ~description:"output_shared targets for native and bytecode (PR #6733)"
+  ~tree:[T.f "hello.ml" ~content:"print_endline \"Hello, World!\"";
+         T.f "_tags" ~content:"<*.so>: runtime_variant(_shared)"]
+  ~targets:("hello.byte.so",["hello.native.so"]) ();;
+
 let () = test "StrictSequenceFlag"
   ~options:[`no_ocamlfind; `quiet]
   ~description:"strict_sequence tag"