diff --git a/dlls/winmm/wineesd/audio.c b/dlls/winmm/wineesd/audio.c
index 5e696f01c0e..62f6fd5e680 100644
--- a/dlls/winmm/wineesd/audio.c
+++ b/dlls/winmm/wineesd/audio.c
@@ -34,6 +34,7 @@
 
 #include "config.h"
 
+#include <errno.h>
 #include <math.h>
 #include <stdlib.h>
 #include <stdarg.h>