diff --git a/builder/Makefile.am b/builder/Makefile.am
index 0a74aa124..1c2206f0a 100644
--- a/builder/Makefile.am
+++ b/builder/Makefile.am
@@ -152,7 +152,7 @@ if HAVE_OCAML_PKG_GETTEXT
 OCAMLPACKAGES += -package gettext-stub
 endif
 
-OCAMLCFLAGS = -g -warn-error CDEFLMPSUVYZX $(OCAMLPACKAGES)
+OCAMLCFLAGS = -g -warn-error CDEFLMPSUVYZX-3 $(OCAMLPACKAGES)
 OCAMLOPTFLAGS = $(OCAMLCFLAGS)
 
 OCAMLCLIBS  = \
diff --git a/customize/Makefile.am b/customize/Makefile.am
index 80fceb366..d1cbc14fa 100644
--- a/customize/Makefile.am
+++ b/customize/Makefile.am
@@ -109,7 +109,7 @@ if HAVE_OCAML_PKG_GETTEXT
 OCAMLPACKAGES += -package gettext-stub
 endif
 
-OCAMLCFLAGS = -g -warn-error CDEFLMPSUVYZX $(OCAMLPACKAGES)
+OCAMLCFLAGS = -g -warn-error CDEFLMPSUVYZX-3 $(OCAMLPACKAGES)
 OCAMLOPTFLAGS = $(OCAMLCFLAGS)
 
 OCAMLCLIBS  = \
diff --git a/generator/Makefile.am b/generator/Makefile.am
index e66644ce3..3716c7702 100644
--- a/generator/Makefile.am
+++ b/generator/Makefile.am
@@ -95,7 +95,7 @@ objects = \
 
 EXTRA_DIST = $(sources) files-generated.txt
 
-OCAMLCFLAGS = -warn-error CDEFLMPSUVYZX -I $(srcdir) -I . -package unix,str
+OCAMLCFLAGS = -warn-error CDEFLMPSUVYZX-3 -I $(srcdir) -I . -package unix,str
 
 noinst_PROGRAM = generator
 
diff --git a/mllib/Makefile.am b/mllib/Makefile.am
index 7c242fca2..2528e7257 100644
--- a/mllib/Makefile.am
+++ b/mllib/Makefile.am
@@ -89,7 +89,7 @@ if HAVE_OCAML_PKG_GETTEXT
 OCAMLPACKAGES += -package gettext-stub
 endif
 
-OCAMLCFLAGS = -g -warn-error CDEFLMPSUVYZX $(OCAMLPACKAGES)
+OCAMLCFLAGS = -g -warn-error CDEFLMPSUVYZX-3 $(OCAMLPACKAGES)
 OCAMLOPTFLAGS = $(OCAMLCFLAGS)
 
 OCAMLCLIBS  = \
diff --git a/ocaml/Makefile.am b/ocaml/Makefile.am
index ee5a24185..8b9dcfa24 100644
--- a/ocaml/Makefile.am
+++ b/ocaml/Makefile.am
@@ -37,7 +37,7 @@ CLEANFILES += t/*.cmi t/*.cmo t/*.cmx t/*.o t/*.a t/*.so
 
 if HAVE_OCAML
 
-OCAMLCFLAGS = -g -warn-error CDEFLMPSUVYZX
+OCAMLCFLAGS = -g -warn-error CDEFLMPSUVYZX-3
 OCAMLOPTFLAGS = $(OCAMLCFLAGS)
 
 noinst_DATA = mlguestfs.cma META
diff --git a/resize/Makefile.am b/resize/Makefile.am
index 4b049ab53..91abeee2c 100644
--- a/resize/Makefile.am
+++ b/resize/Makefile.am
@@ -67,7 +67,7 @@ if HAVE_OCAML_PKG_GETTEXT
 OCAMLPACKAGES += -package gettext-stub
 endif
 
-OCAMLCFLAGS = -g -warn-error CDEFLMPSUVYZX $(OCAMLPACKAGES)
+OCAMLCFLAGS = -g -warn-error CDEFLMPSUVYZX-3 $(OCAMLPACKAGES)
 OCAMLOPTFLAGS = $(OCAMLCFLAGS)
 
 OCAMLCLIBS  = \
diff --git a/sparsify/Makefile.am b/sparsify/Makefile.am
index 7733dab02..3dde57b51 100644
--- a/sparsify/Makefile.am
+++ b/sparsify/Makefile.am
@@ -70,7 +70,7 @@ if HAVE_OCAML_PKG_GETTEXT
 OCAMLPACKAGES += -package gettext-stub
 endif
 
-OCAMLFLAGS = -g -warn-error CDEFLMPSUVYZX
+OCAMLFLAGS = -g -warn-error CDEFLMPSUVYZX-3
 
 if !HAVE_OCAMLOPT
 OBJECTS = $(BOBJECTS)
diff --git a/sysprep/Makefile.am b/sysprep/Makefile.am
index cc411ccf2..06eec8606 100644
--- a/sysprep/Makefile.am
+++ b/sysprep/Makefile.am
@@ -125,7 +125,7 @@ if HAVE_OCAML_PKG_GETTEXT
 OCAMLPACKAGES += -package gettext-stub
 endif
 
-OCAMLCFLAGS = -g -warn-error CDEFLMPSUVYZX $(OCAMLPACKAGES)
+OCAMLCFLAGS = -g -warn-error CDEFLMPSUVYZX-3 $(OCAMLPACKAGES)
 OCAMLOPTFLAGS = $(OCAMLCFLAGS)
 
 OCAMLCLIBS  = \
diff --git a/v2v/Makefile.am b/v2v/Makefile.am
index a1dec5245..a62e191a6 100644
--- a/v2v/Makefile.am
+++ b/v2v/Makefile.am
@@ -87,7 +87,7 @@ if HAVE_OCAML_PKG_GETTEXT
 OCAMLPACKAGES += -package gettext-stub
 endif
 
-OCAMLFLAGS = -g -warn-error CDEFLMPSUVYZX
+OCAMLFLAGS = -g -warn-error CDEFLMPSUVYZX-3
 
 if !HAVE_OCAMLOPT
 OBJECTS = $(BOBJECTS)