diff --git a/src/beep.h b/src/beep.h
index c4d77f1..aa5c58b 100644
--- a/src/beep.h
+++ b/src/beep.h
@@ -4,7 +4,7 @@
 #define PORTAUDIO
 #endif
 
-#ifdef __ARM__
+#ifdef __arm__
 #define ALSA
 #endif