docs: Note the lowest supported Emscripten version. Reference Issue #6304.
diff --git a/docs/README-emscripten.md b/docs/README-emscripten.md
index b535cc6..7e9880b 100644
--- a/docs/README-emscripten.md
+++ b/docs/README-emscripten.md
@@ -1,6 +1,10 @@
Emscripten
================================================================================
+SDL currently requires at least Emscripten 2.0.32 to build. Newer versions
+are likely to work, as well.
+
+
Build:
$ mkdir build