--- ./pkg/topkg.ml
+++ ./pkg/topkg.ml
@@ -344,7 +344,7 @@
   let build ccomp btool bdir pkg mvs =
     let ext_to_string = Exts.ext_to_string ccomp in
     let install, exec = build_strings btool bdir ext_to_string mvs in
-    let e = Sys.command exec in
+    let e = Sys.command ("bash -c '" ^ exec ^ "'") in
     if e <> 0 then exit e else
     let install_file = pkg ^ ".install" in
     try
