diff --git a/arch/i386/bits/errno.h b/arch/i386/bits/errno.h
index ec3d3633..c75720ef 100644
--- a/arch/i386/bits/errno.h
+++ b/arch/i386/bits/errno.h
@@ -93,6 +93,7 @@
 #define EPROTONOSUPPORT 93
 #define ESOCKTNOSUPPORT 94
 #define EOPNOTSUPP      95
+#define ENOTSUP         EOPNOTSUPP
 #define EPFNOSUPPORT    96
 #define EAFNOSUPPORT    97
 #define EADDRINUSE      98
diff --git a/arch/x86_64/bits/errno.h b/arch/x86_64/bits/errno.h
index ec3d3633..c75720ef 100644
--- a/arch/x86_64/bits/errno.h
+++ b/arch/x86_64/bits/errno.h
@@ -93,6 +93,7 @@
 #define EPROTONOSUPPORT 93
 #define ESOCKTNOSUPPORT 94
 #define EOPNOTSUPP      95
+#define ENOTSUP         EOPNOTSUPP
 #define EPFNOSUPPORT    96
 #define EAFNOSUPPORT    97
 #define EADDRINUSE      98