diff --git a/dlls/winmm/wineoss/mixer.c b/dlls/winmm/wineoss/mixer.c
index 07a5fcaad37d7d9af03e1299f4f3282bf3ced038..5e334355e6150b4a706a56d1692c832559730e56 100644
--- a/dlls/winmm/wineoss/mixer.c
+++ b/dlls/winmm/wineoss/mixer.c
@@ -14,6 +14,7 @@
 #include <string.h>
 #include <unistd.h>
 #include <fcntl.h>
+#include <errno.h>
 #include <sys/ioctl.h>
 #include "windef.h"
 #include "mmddk.h"