diff --git a/byterun/Makefile b/byterun/Makefile
deleted file mode 100644
index 3ff28684f..000000000
--- a/byterun/Makefile
+++ /dev/null
@@ -1,10 +0,0 @@
-FLAGS=-g -fstack-protector-all
-
-all: byterun.o
-	$(CC) $(FLAGS) -o byterun byterun.o ../runtime/runtime.a
-
-byterun.o: byterun.c
-	$(CC) $(FLAGS) -g -c byterun.c
-
-clean:
-	$(RM) *.a *.o *~ byterun
diff --git a/performance/Makefile b/performance/Makefile
deleted file mode 100644
index 3848042f8..000000000
--- a/performance/Makefile
+++ /dev/null
@@ -1,14 +0,0 @@
-TESTS=$(sort $(basename $(wildcard *.lama)))
-
-LAMAC=../src/lamac
-
-.PHONY: check $(TESTS)
-
-check: $(TESTS)
-
-$(TESTS): %: %.lama
-	@echo $@
-	LAMA=../runtime $(LAMAC)  $< && `which time` -f "$@\t%U" ./$@
-
-clean:
-	$(RM) test*.log *.s *~ $(TESTS) *.i
diff --git a/runtime/Makefile b/runtime/Makefile
index 039eda815..1d5fe82a1 100644
--- a/runtime/Makefile
+++ b/runtime/Makefile
@@ -28,3 +28,4 @@ printf.o: printf.S
 
 clean:
 	$(RM) *.a *.o *~ negative_scenarios/*.err
+
diff --git a/runtime32/dune b/runtime32/dune
index fd1d8ae0c..47f248da2 100644
--- a/runtime32/dune
+++ b/runtime32/dune
@@ -1,7 +1,7 @@
 (rule
  (target runtime.a)
  (enabled_if
-  (<> %{ocaml-config:os_type} "Darwin"))
+  (= %{system} "linux"))
  (mode
   (promote (until-clean)))
  (deps Makefile gc_runtime.s runtime.c runtime.h)
diff --git a/stdlib/x32/dune b/stdlib/x32/dune
index 8ada8a8bf..75d89f945 100644
--- a/stdlib/x32/dune
+++ b/stdlib/x32/dune
@@ -1,6 +1,6 @@
 (rule
  (enabled_if
-  (<> %{ocaml-config:os_type} "Darwin"))
+  (= %{system} "linux"))
  (deps
   ../Makefile
   ../../runtime32/Std.i
diff --git a/tools/Makefile b/tools/Makefile
deleted file mode 100644
index 6e6535403..000000000
--- a/tools/Makefile
+++ /dev/null
@@ -1,25 +0,0 @@
-.PHONY: clean
-
-GTD = tool.exe
-
-LAMA_CMXES = ../src/Language.cmx
-OCAMLC = ocamlfind c
-OCAMLOPT = ocamlfind opt
-BFLAGS += -package GT,ostap,re,str -I ../src -rectypes -g
-
-all: $(GTD) $(OUT2)
-
-
-
-$(GTD): tool.cmx
-	$(OCAMLOPT) $(BFLAGS) $(LAMA_CMXES) -linkpkg $^ -o $@
-
-
-clean:
-	$(RM) *.cmi *.cmo *.cmx *.annot *.o *.opt *.byte *~ .depend $(OUT) $(GENERATED)
-
-%.cmi: %.ml
-	$(OCAMLC) -c $(BFLAGS)  $<
-
-%.cmx: %.ml
-	$(OCAMLOPT) -c $(BFLAGS) $<
diff --git a/tutorial/dune b/tutorial/dune
index ac74d1d45..c819d913d 100644
--- a/tutorial/dune
+++ b/tutorial/dune
@@ -1,7 +1,7 @@
 
 (rule
  (targets Expressions.x32.exe)
- (enabled_if (<> %{ocaml-config:os_type} "Darwin"))
+ (enabled_if (= %{ocaml-config:os_type} "linux"))
  (deps (:lama Expressions.lama) ../runtime32/runtime.a ../stdlib/x32/Fun.i)
  (mode
   (promote (until-clean)))
@@ -43,7 +43,7 @@
 
 (rule
  (targets Functions.x32.exe)
- (enabled_if (<> %{ocaml-config:os_type} "Darwin"))
+ (enabled_if (= %{ocaml-config:os_type} "linux"))
  (deps (:lama Functions.lama) ../runtime32/runtime.a ../stdlib/x32/Fun.i)
  (mode
   (promote (until-clean)))
@@ -85,7 +85,7 @@
 
 (rule
  (targets Hello.x32.exe)
- (enabled_if (<> %{ocaml-config:os_type} "Darwin"))
+ (enabled_if (= %{ocaml-config:os_type} "linux"))
  (deps (:lama Hello.lama) ../runtime32/runtime.a ../stdlib/x32/Fun.i)
  (mode
   (promote (until-clean)))
@@ -127,7 +127,7 @@
 
 (rule
  (targets PatternMatching.x32.exe)
- (enabled_if (<> %{ocaml-config:os_type} "Darwin"))
+ (enabled_if (= %{ocaml-config:os_type} "linux"))
  (deps (:lama PatternMatching.lama) ../runtime32/runtime.a ../stdlib/x32/Fun.i)
  (mode
   (promote (until-clean)))
@@ -169,7 +169,7 @@
 
 (rule
  (targets Values.x32.exe)
- (enabled_if (<> %{ocaml-config:os_type} "Darwin"))
+ (enabled_if (= %{ocaml-config:os_type} "linux"))
  (deps (:lama Values.lama) ../runtime32/runtime.a ../stdlib/x32/Fun.i)
  (mode
   (promote (until-clean)))
diff --git a/tutorial/gen.ml b/tutorial/gen.ml
index 1e296c4f8..a798ef28b 100644
--- a/tutorial/gen.ml
+++ b/tutorial/gen.ml
@@ -31,7 +31,7 @@ let () =
       template
       |> Str.global_replace (Str.regexp "%DEMO%") (demo^".x32")
       |> Str.global_replace (Str.regexp "%DEMOSRC%") demo
-      |> Str.global_replace (Str.regexp "%COND%") {|(enabled_if (<> %{ocaml-config:os_type} "Darwin"))|}
+      |> Str.global_replace (Str.regexp "%COND%") {|(enabled_if (= %{ocaml-config:os_type} "linux"))|}
       |> Str.global_replace (Str.regexp "%RUNTIME%") "../runtime32"
       |> Str.global_replace (Str.regexp "%STDLIB%") "../stdlib/x32"
       |> Str.global_replace (Str.regexp "%EXTRASWITCHES%") "-march=x86"