diff --git a/appveyor.yml b/appveyor.yml
index 4edcd7a7f..3ddec6dfb 100644
--- a/appveyor.yml
+++ b/appveyor.yml
@@ -11,6 +11,7 @@ environment:
  SDL2_MIXER_URL: https://www.libsdl.org/projects/SDL_mixer/release/SDL2_mixer-devel-2.0.1-mingw.tar.gz
  SDL2_MIXER_ARCHIVE: SDL2_mixer-devel-2.0.1-mingw.tar
  SDL2_MIXER_MOVE: SDL2_mixer-2.0.1\i686-w64-mingw32
+ CFLAGS: -Wall -W -Werror
 
 cache:
 - SDL2-devel-2.0.4-mingw.tar.gz