am ca15af1b: Merge "Turn on -Werror=implicit-function-declaration for arm64."

* commit 'ca15af1bcde972b6ba3546d45913c9bb51bd93b0':
  Turn on -Werror=implicit-function-declaration for arm64.
diff --git a/core/combo/TARGET_linux-arm64.mk b/core/combo/TARGET_linux-arm64.mk
index abd8e3a..07a1de9 100644
--- a/core/combo/TARGET_linux-arm64.mk
+++ b/core/combo/TARGET_linux-arm64.mk
@@ -91,6 +91,7 @@
 TARGET_GLOBAL_CFLAGS += \
     -Werror=pointer-to-int-cast \
     -Werror=int-to-pointer-cast \
+    -Werror=implicit-function-declaration \
 
 TARGET_GLOBAL_CFLAGS += -fno-strict-volatile-bitfields