diff --git a/stdlib/public/Platform/WASILibc.swift.gyb b/stdlib/public/Platform/WASILibc.swift.gyb
index f3d5f2486701a..9331e3f6a8420 100644
--- a/stdlib/public/Platform/WASILibc.swift.gyb
+++ b/stdlib/public/Platform/WASILibc.swift.gyb
@@ -73,6 +73,7 @@ posix_error_codes = [
   "EADDRNOTAVAIL",
   "EAFNOSUPPORT",
   "EAGAIN",
+  "EWOULDBLOCK",
   "EALREADY",
   "EBADF",
   "EBADMSG",
@@ -125,6 +126,7 @@ posix_error_codes = [
   "ENOTRECOVERABLE",
   "ENOTSOCK",
   "ENOTSUP",
+  "EOPNOTSUPP",
   "ENOTTY",
   "ENXIO",
   "EOVERFLOW",