diff --git a/configure.ac b/configure.ac
index 50aa50e4..0270e9da 100644
--- a/configure.ac
+++ b/configure.ac
@@ -770,8 +770,8 @@ AC_COMPILE_IFELSE([AC_LANG_PROGRAM([[
 #ifndef NATIVE_LITTLE_ENDIAN
 # error libsodium currently expects a little endian CPU for the 128-bit type
 #endif
-#ifdef __wasm__
-# error 128-bit arithmetic in WebAssembly is slow
+#ifdef __EMSCRIPTEN__
+# error emscripten currently doesn't support some operations on integers larger than 64 bits
 #endif
 #include <stddef.h>
 #include <stdint.h>