diff --git a/osdep/io.h b/osdep/io.h
index aa20446210..9f715d904e 100644
--- a/osdep/io.h
+++ b/osdep/io.h
@@ -26,6 +26,10 @@
 #include <sys/stat.h>
 #include <fcntl.h>
 
+#ifndef O_BINARY
+#define O_BINARY 0
+#endif
+
 // This is in POSIX.1-2008, but support outside of Linux is scarce.
 #ifndef O_CLOEXEC
 #define O_CLOEXEC 0
diff --git a/stream/stream.h b/stream/stream.h
index e1dc2a91d0..7d10eccd28 100644
--- a/stream/stream.h
+++ b/stream/stream.h
@@ -30,10 +30,6 @@
 
 #include "bstr/bstr.h"
 
-#ifndef O_BINARY
-#define O_BINARY 0
-#endif
-
 enum streamtype {
     STREAMTYPE_GENERIC = 0,
     STREAMTYPE_FILE,