diff --git a/lib/src/portable/endian.h b/lib/src/portable/endian.h
index 47e315f4..f467ec53 100644
--- a/lib/src/portable/endian.h
+++ b/lib/src/portable/endian.h
@@ -23,7 +23,8 @@
     defined(__OpenBSD__) || \
     defined(__CYGWIN__) || \
     defined(__MSYS__) || \
-    defined(__EMSCRIPTEN__)
+    defined(__EMSCRIPTEN__) || \
+    defined(__wasi__)
 
 #if defined(__NetBSD__)
 #define _NETBSD_SOURCE 1