diff --git a/builder/builtins.go b/builder/builtins.go
index 1feeb5d5a..60db1f28d 100644
--- a/builder/builtins.go
+++ b/builder/builtins.go
@@ -204,7 +204,8 @@ var avrBuiltins = []string{
 
 // Builtins needed specifically for windows/386.
 var windowsI386Builtins = []string{
-	"i386/chkstk.S", // also _alloca
+	"i386/chkstk.S",  // __chkstk_ms
+	"i386/chkstk2.S", // _alloca (__alloca)
 }
 
 // Builtins needed specifically for windows/amd64.