diff --git a/deps/zlib-1.2.11/src/gzlib.c b/deps/zlib-1.2.11/src/gzlib.c
index f3bd685be0..4c135aabff 100644
--- a/deps/zlib-1.2.11/src/gzlib.c
+++ b/deps/zlib-1.2.11/src/gzlib.c
@@ -5,6 +5,10 @@
 #include <stdint.h>
 #include "gzguts.h"
 
+#ifndef O_BINARY
+  #define O_BINARY 0
+#endif
+
 #if defined(_WIN32) && !defined(__BORLANDC__) && !defined(__MINGW32__)
 #  define LSEEK _lseeki64
 #else
diff --git a/src/os/inc/osDef.h b/src/os/inc/osDef.h
index d718bef6da..bdbe95a75d 100644
--- a/src/os/inc/osDef.h
+++ b/src/os/inc/osDef.h
@@ -20,6 +20,10 @@
 extern "C" {
 #endif
 
+#ifndef O_BINARY
+  #define O_BINARY 0
+#endif
+
 #ifndef STDERR_FILENO
 #define STDERR_FILENO (2)
 #endif