diff --git a/src/gendef.mk b/src/gendef.mk
index 46115a00..9b5cf6d3 100644
--- a/src/gendef.mk
+++ b/src/gendef.mk
@@ -16,6 +16,7 @@ endef
 
 define $(PKG)_BUILD
     cd '$(1)/mingw-w64-tools/gendef' && ./configure \
+        CFLAGS='-Wno-implicit-fallthrough' \
         --host='$(BUILD)' \
         --build='$(BUILD)' \
         --prefix='$(PREFIX)/$(TARGET)' \