diff --git a/tools/firmware-utils/Makefile b/tools/firmware-utils/Makefile
index 7745b7bab2..76d5929af5 100644
--- a/tools/firmware-utils/Makefile
+++ b/tools/firmware-utils/Makefile
@@ -85,7 +85,7 @@ define Host/Compile
 	$(call cc,mkdlinkfw mkdlinkfw-lib, -lz -Wall --std=c99)
 	$(call cc,dns313-header, -Wall)
 	$(call cc,mksercommfw, -Wall)
-	$(call cc,nec-enc, -Wall)
+	$(call cc,nec-enc, -Wall --std=gnu99)
 endef
 
 define Host/Install