diff --git a/core/combo/TARGET_linux-x86_64.mk b/core/combo/TARGET_linux-x86_64.mk
index d92e974a3c..046a42bb56 100644
--- a/core/combo/TARGET_linux-x86_64.mk
+++ b/core/combo/TARGET_linux-x86_64.mk
@@ -97,6 +97,7 @@ TARGET_GLOBAL_CFLAGS += \
 TARGET_GLOBAL_CFLAGS += \
     -Werror=pointer-to-int-cast \
     -Werror=int-to-pointer-cast \
+    -Werror=implicit-function-declaration \
 
 android_config_h := $(call select-android-config-h,target_linux-x86)
 TARGET_ANDROID_CONFIG_CFLAGS := -include $(android_config_h) -I $(dir $(android_config_h))