diff --git a/engine.mk b/engine.mk
index 4a6e7b92..32cfc200 100644
--- a/engine.mk
+++ b/engine.mk
@@ -52,7 +52,7 @@ CONFIGHEADER := $(BUILDDIR)/config.h
 GLOBAL_INCLUDES := $(BUILDDIR) $(addsuffix /include,$(LKINC))
 GLOBAL_OPTFLAGS ?= $(ARCH_OPTFLAGS)
 GLOBAL_COMPILEFLAGS := -g -fno-builtin -finline -include $(CONFIGHEADER)
-GLOBAL_COMPILEFLAGS += -W -Wall -Wno-multichar -Wno-unused-parameter -Wno-unused-function -Wno-unused-label
+GLOBAL_COMPILEFLAGS += -W -Wall -Wno-multichar -Wno-unused-parameter -Wno-unused-function -Wno-unused-label -Werror=return-type
 GLOBAL_CFLAGS := --std=gnu99 -Werror-implicit-function-declaration -Wstrict-prototypes -Wwrite-strings
 #GLOBAL_CFLAGS += -Werror
 GLOBAL_CPPFLAGS := -fno-exceptions -fno-rtti -fno-threadsafe-statics