diff -r 8e38c8405788 -r b8b97c49e339 src/Pure/Admin/build_csdp.scala
--- a/src/Pure/Admin/build_csdp.scala	Sat Oct 10 22:04:51 2020 +0200
+++ b/src/Pure/Admin/build_csdp.scala	Sat Oct 10 22:05:47 2020 +0200
@@ -201,7 +201,7 @@
   Build prover component from official downloads.
 """,
         "D:" -> (arg => target_dir = Path.explode(arg)),
-        "M:" -> (arg => mingw = MinGW.root(Path.explode(arg))),
+        "M:" -> (arg => mingw = MinGW(Path.explode(arg))),
         "U:" -> (arg => download_url = arg),
         "v" -> (_ => verbose = true))