diff --git a/src/api/ocaml/cloudi.ml b/src/api/ocaml/cloudi.ml
index ec72e7ed..96eb404c 100644
--- a/src/api/ocaml/cloudi.ml
+++ b/src/api/ocaml/cloudi.ml
@@ -59,7 +59,7 @@ type callback_result =
 
 module Instance = struct
   type 's t = {
-      mutable state : 's;
+      state : 's;
       terminate_exception : bool;
       socket : Unix.file_descr;
       use_header : bool;
diff --git a/src/tests/count/ocaml/Makefile.am b/src/tests/count/ocaml/Makefile.am
index a2b8bba8..9d88d5cb 100644
--- a/src/tests/count/ocaml/Makefile.am
+++ b/src/tests/count/ocaml/Makefile.am
@@ -7,17 +7,15 @@ OCAMLDEPS = str.cmxa unix.cmxa threads/threads.cmxa \
             $(top_builddir)/api/ocaml/external/nums.cmxa \
             -ccopt -L$(top_builddir)/api/ocaml/external/ \
             $(top_builddir)/api/ocaml/cloudi.cmxa
-SUFFIXES = .ml .cmx
 
 all-local: count_ocaml
 
-count_ocaml: main.cmx
+count_ocaml: main.mli main.ml
+	$(OCAMLC) $(OCAMLFLAGS) -o main.cmi -c $(srcdir)/main.mli
+	$(OCAMLOPT) $(OCAMLFLAGS) -o main.cmx -c \
+                -I $(top_builddir)/api/ocaml/ -thread $(srcdir)/main.ml
 	$(OCAMLOPT) -o count_ocaml $(OCAMLDEPS) main.cmx
 
-.ml.cmx:
-	$(OCAMLOPT) $(OCAMLFLAGS) -o $@ -c \
-                -I $(top_builddir)/api/ocaml/ -thread $<
-
 install-exec-hook: count_ocaml
 	$(MKDIR_P) $(instdir)
 	$(INSTALL_SCRIPT) count_ocaml $(instdir)
diff --git a/src/tests/count/ocaml/main.mli b/src/tests/count/ocaml/main.mli
new file mode 100644
index 00000000..b94fb2ef
--- /dev/null
+++ b/src/tests/count/ocaml/main.mli
@@ -0,0 +1,9 @@
+(*-*-Mode:ocaml;coding:utf-8;tab-width:2;c-basic-offset:2;indent-tabs-mode:()-*-
+  ex: set ft=ocaml fenc=utf-8 sts=2 ts=2 sw=2 et nomod: *)
+
+(*
+
+  This page intentionally left blank.
+
+ *)
+
diff --git a/src/tests/http_req/ocaml/Makefile.am b/src/tests/http_req/ocaml/Makefile.am
index c50b2d69..babd1b1a 100644
--- a/src/tests/http_req/ocaml/Makefile.am
+++ b/src/tests/http_req/ocaml/Makefile.am
@@ -7,17 +7,15 @@ OCAMLDEPS = str.cmxa unix.cmxa threads/threads.cmxa \
             $(top_builddir)/api/ocaml/external/nums.cmxa \
             -ccopt -L$(top_builddir)/api/ocaml/external/ \
             $(top_builddir)/api/ocaml/cloudi.cmxa
-SUFFIXES = .ml .cmx
 
 all-local: http_req_ocaml
 
-http_req_ocaml: main.cmx
+http_req_ocaml: main.mli main.ml
+	$(OCAMLC) $(OCAMLFLAGS) -o main.cmi -c $(srcdir)/main.mli
+	$(OCAMLOPT) $(OCAMLFLAGS) -o main.cmx -c \
+                -I $(top_builddir)/api/ocaml/ -thread $(srcdir)/main.ml
 	$(OCAMLOPT) -o http_req_ocaml $(OCAMLDEPS) main.cmx
 
-.ml.cmx:
-	$(OCAMLOPT) $(OCAMLFLAGS) -o $@ -c \
-                -I $(top_builddir)/api/ocaml/ -thread $<
-
 install-exec-hook: http_req_ocaml
 	$(MKDIR_P) $(instdir)
 	$(INSTALL_SCRIPT) http_req_ocaml $(instdir)
diff --git a/src/tests/http_req/ocaml/main.mli b/src/tests/http_req/ocaml/main.mli
new file mode 100644
index 00000000..b94fb2ef
--- /dev/null
+++ b/src/tests/http_req/ocaml/main.mli
@@ -0,0 +1,9 @@
+(*-*-Mode:ocaml;coding:utf-8;tab-width:2;c-basic-offset:2;indent-tabs-mode:()-*-
+  ex: set ft=ocaml fenc=utf-8 sts=2 ts=2 sw=2 et nomod: *)
+
+(*
+
+  This page intentionally left blank.
+
+ *)
+
diff --git a/src/tests/messaging/ocaml/Makefile.am b/src/tests/messaging/ocaml/Makefile.am
index 7e2d21b3..fe97669a 100644
--- a/src/tests/messaging/ocaml/Makefile.am
+++ b/src/tests/messaging/ocaml/Makefile.am
@@ -7,17 +7,15 @@ OCAMLDEPS = str.cmxa unix.cmxa threads/threads.cmxa \
             $(top_builddir)/api/ocaml/external/nums.cmxa \
             -ccopt -L$(top_builddir)/api/ocaml/external/ \
             $(top_builddir)/api/ocaml/cloudi.cmxa
-SUFFIXES = .ml .cmx
 
 all-local: messaging_ocaml
 
-messaging_ocaml: main.cmx
+messaging_ocaml: main.mli main.ml
+	$(OCAMLC) $(OCAMLFLAGS) -o main.cmi -c $(srcdir)/main.mli
+	$(OCAMLOPT) $(OCAMLFLAGS) -o main.cmx -c \
+                -I $(top_builddir)/api/ocaml/ -thread $(srcdir)/main.ml
 	$(OCAMLOPT) -o messaging_ocaml $(OCAMLDEPS) main.cmx
 
-.ml.cmx:
-	$(OCAMLOPT) $(OCAMLFLAGS) -o $@ -c \
-                -I $(top_builddir)/api/ocaml/ -thread $<
-
 install-exec-hook: messaging_ocaml
 	$(MKDIR_P) $(instdir)
 	$(INSTALL_SCRIPT) messaging_ocaml $(instdir)
diff --git a/src/tests/messaging/ocaml/main.mli b/src/tests/messaging/ocaml/main.mli
new file mode 100644
index 00000000..b94fb2ef
--- /dev/null
+++ b/src/tests/messaging/ocaml/main.mli
@@ -0,0 +1,9 @@
+(*-*-Mode:ocaml;coding:utf-8;tab-width:2;c-basic-offset:2;indent-tabs-mode:()-*-
+  ex: set ft=ocaml fenc=utf-8 sts=2 ts=2 sw=2 et nomod: *)
+
+(*
+
+  This page intentionally left blank.
+
+ *)
+
diff --git a/src/tests/msg_size/ocaml/Makefile.am b/src/tests/msg_size/ocaml/Makefile.am
index af034426..2757e496 100644
--- a/src/tests/msg_size/ocaml/Makefile.am
+++ b/src/tests/msg_size/ocaml/Makefile.am
@@ -7,17 +7,15 @@ OCAMLDEPS = str.cmxa unix.cmxa threads/threads.cmxa \
             $(top_builddir)/api/ocaml/external/nums.cmxa \
             -ccopt -L$(top_builddir)/api/ocaml/external/ \
             $(top_builddir)/api/ocaml/cloudi.cmxa
-SUFFIXES = .ml .cmx
 
 all-local: msg_size_ocaml
 
-msg_size_ocaml: main.cmx
+msg_size_ocaml: main.mli main.ml
+	$(OCAMLC) $(OCAMLFLAGS) -o main.cmi -c $(srcdir)/main.mli
+	$(OCAMLOPT) $(OCAMLFLAGS) -o main.cmx -c \
+                -I $(top_builddir)/api/ocaml/ -thread $(srcdir)/main.ml
 	$(OCAMLOPT) -o msg_size_ocaml $(OCAMLDEPS) main.cmx
 
-.ml.cmx:
-	$(OCAMLOPT) $(OCAMLFLAGS) -o $@ -c \
-                -I $(top_builddir)/api/ocaml/ -thread $<
-
 install-exec-hook: msg_size_ocaml
 	$(MKDIR_P) $(instdir)
 	$(INSTALL_SCRIPT) msg_size_ocaml $(instdir)
diff --git a/src/tests/msg_size/ocaml/main.mli b/src/tests/msg_size/ocaml/main.mli
new file mode 100644
index 00000000..b94fb2ef
--- /dev/null
+++ b/src/tests/msg_size/ocaml/main.mli
@@ -0,0 +1,9 @@
+(*-*-Mode:ocaml;coding:utf-8;tab-width:2;c-basic-offset:2;indent-tabs-mode:()-*-
+  ex: set ft=ocaml fenc=utf-8 sts=2 ts=2 sw=2 et nomod: *)
+
+(*
+
+  This page intentionally left blank.
+
+ *)
+
diff --git a/src/tests/null/ocaml/Makefile.am b/src/tests/null/ocaml/Makefile.am
index cba62d12..7f7cb662 100644
--- a/src/tests/null/ocaml/Makefile.am
+++ b/src/tests/null/ocaml/Makefile.am
@@ -7,17 +7,15 @@ OCAMLDEPS = str.cmxa unix.cmxa threads/threads.cmxa \
             $(top_builddir)/api/ocaml/external/nums.cmxa \
             -ccopt -L$(top_builddir)/api/ocaml/external/ \
             $(top_builddir)/api/ocaml/cloudi.cmxa
-SUFFIXES = .ml .cmx
 
 all-local: null_ocaml
 
-null_ocaml: main.cmx
+null_ocaml: main.mli main.ml
+	$(OCAMLC) $(OCAMLFLAGS) -o main.cmi -c $(srcdir)/main.mli
+	$(OCAMLOPT) $(OCAMLFLAGS) -o main.cmx -c \
+                -I $(top_builddir)/api/ocaml/ -thread $(srcdir)/main.ml
 	$(OCAMLOPT) -o null_ocaml $(OCAMLDEPS) main.cmx
 
-.ml.cmx:
-	$(OCAMLOPT) $(OCAMLFLAGS) -o $@ -c \
-                -I $(top_builddir)/api/ocaml/ -thread $<
-
 install-exec-hook: null_ocaml
 	$(MKDIR_P) $(instdir)
 	$(INSTALL_SCRIPT) null_ocaml $(instdir)
diff --git a/src/tests/null/ocaml/main.mli b/src/tests/null/ocaml/main.mli
new file mode 100644
index 00000000..b94fb2ef
--- /dev/null
+++ b/src/tests/null/ocaml/main.mli
@@ -0,0 +1,9 @@
+(*-*-Mode:ocaml;coding:utf-8;tab-width:2;c-basic-offset:2;indent-tabs-mode:()-*-
+  ex: set ft=ocaml fenc=utf-8 sts=2 ts=2 sw=2 et nomod: *)
+
+(*
+
+  This page intentionally left blank.
+
+ *)
+