diff --git a/flake.nix b/flake.nix
index 17dab19..68f0318 100644
--- a/flake.nix
+++ b/flake.nix
@@ -11,7 +11,7 @@
 
           verilator = import ./verilator.nix pkgs ;
 
-          vflags = "-Wpedantic -Wwarn-lint -Wwarn-style";
+          vflags = "-Wpedantic -Wwarn-lint -Wwarn-style -CFLAGS -Wpedantic";
           verilate-src = cmd: ''
             cp -r ${./verilog-src} ./verilog-src
             cp -r ${./simulation} ./simulation