diff --git a/Makefile b/Makefile
index 92ef5cef19d044f71cc5fc75009be091bc127b3d..2a2deee009cc7689efb5546f0152270fca641318 100644
--- a/Makefile
+++ b/Makefile
@@ -1426,7 +1426,7 @@ else
     $(sort $(shell find $(TEST_DIRS_AS_PLUGIN:%=tests/%) -not -path '*/\.*' -name '*.ml'))
 endif
 $(foreach file,$(LONELY_TESTS_ML_FILES),\
-  $(eval $(file:%.ml=%.cmo): BFLAGS+=-I $(dir $(file))))
+  $(eval $(file:%.ml=%.cmo): BFLAGS+=-w -70 -I $(dir $(file))))
 $(foreach file,$(LONELY_TESTS_ML_FILES),\
   $(eval $(file:%.ml=%.cmx): OFLAGS+=-I $(dir $(file))))
 $(foreach file,$(LONELY_TESTS_ML_FILES),\
diff --git a/share/Makefile.plugin.template b/share/Makefile.plugin.template
index 9e6c6d6848b8318eaaed8535d448e83b4639e89f..ca77423063136672f4335cfd2192a467e2580977 100644
--- a/share/Makefile.plugin.template
+++ b/share/Makefile.plugin.template
@@ -444,7 +444,7 @@ $(NAME_OFLAGS):=$(OFLAGS) $(INCLUDE_FLAGS) $(PLUGIN_OFLAGS)
 # DO NOT include the plugin's own directory as search path for compiling
 # ml test scripts: they will be loaded in a separate phase, and will only see
 # the plugin through its static API
-$(NAME_TEST_BFLAGS):= $(BFLAGS) $(INCLUDE_EXT_FLAGS) $(PLUGIN_BFLAGS)
+$(NAME_TEST_BFLAGS):= $(BFLAGS) -w -70 $(INCLUDE_EXT_FLAGS) $(PLUGIN_BFLAGS)
 $(NAME_TEST_OFLAGS):= $(OFLAGS) $(INCLUDE_EXT_FLAGS) $(PLUGIN_OFLAGS)
 
 $(TARGET_BFLAGS):= $(PLUGIN_LINK_BFLAGS)