diff --git a/vulkan/vkjson/vkjson.cc b/vulkan/vkjson/vkjson.cc
index 3cb9405..8c0cce2 100644
--- a/vulkan/vkjson/vkjson.cc
+++ b/vulkan/vkjson/vkjson.cc
@@ -38,6 +38,12 @@
 
 namespace {
 
+/*
+ * Annotation to tell clang that we intend to fall through from one case to
+ * another in a switch. Sourced from android-base/macros.h.
+ */
+#define FALLTHROUGH_INTENDED [[clang::fallthrough]]
+
 inline bool IsIntegral(double value) {
 #if defined(ANDROID)
   // Android NDK doesn't provide std::trunc yet
diff --git a/vulkan/vkjson/vkjson.h b/vulkan/vkjson/vkjson.h
index 28de680..5818c73 100644
--- a/vulkan/vkjson/vkjson.h
+++ b/vulkan/vkjson/vkjson.h
@@ -33,12 +33,6 @@
 #undef max
 #endif
 
-/*
- * Annotation to tell clang that we intend to fall through from one case to
- * another in a switch. Sourced from android-base/macros.h.
- */
-#define FALLTHROUGH_INTENDED [[clang::fallthrough]]
-
 struct VkJsonLayer {
   VkLayerProperties properties;
   std::vector<VkExtensionProperties> extensions;