diff --git a/byterun/dune b/byterun/dune
index 21ba79084..f5977e598 100644
--- a/byterun/dune
+++ b/byterun/dune
@@ -6,4 +6,24 @@
  (mode
   (promote (until-clean)))
  (action
-  (run gcc -g %{main} %{runtime} -o %{target})))
+  (run gcc %{read:mac-specific-flags.txt} -g %{main} %{runtime} -o %{target})))
+
+(rule
+ (target mac-specific-flags.txt)
+ (enabled_if
+  (= %{system} "linux"))
+ (action
+  (progn
+   (with-stdout-to
+    %{target}
+    (run printf "-g")))))
+
+(rule
+ (target mac-specific-flags.txt)
+ (enabled_if
+  (= %{system} "darwin"))
+ (action
+  (progn
+   (with-stdout-to
+    %{target}
+    (run printf "-arch x86_64 -ld_classic")))))