diff --git a/build-aux/build-mes.sh b/build-aux/build-mes.sh
index f4cc4229..4ced2ed0 100755
--- a/build-aux/build-mes.sh
+++ b/build-aux/build-mes.sh
@@ -1,7 +1,7 @@
 #! /bin/sh
 
 # GNU Mes --- Maxwell Equations of Software
-# Copyright © 2019 Jan (janneke) Nieuwenhuizen <janneke@gnu.org>
+# Copyright © 2019,2021 Jan (janneke) Nieuwenhuizen <janneke@gnu.org>
 #
 # This file is part of GNU Mes.
 #
@@ -60,5 +60,8 @@ then
   # See <https://www.openwall.com/lists/musl/2018/05/09/1>.
   LIBS="${LIBS} -lgcc -lc"
 fi
+if [ "$compiler" = "mescc" ]; then
+   LIBS="${LIBS} -lc -lmescc"
+fi
 link bin/mes-$compiler
 cp bin/mes-$compiler bin/mes
diff --git a/module/mescc/mescc.scm b/module/mescc/mescc.scm
index bb2bd6ae..265215e9 100644
--- a/module/mescc/mescc.scm
+++ b/module/mescc/mescc.scm
@@ -1,5 +1,5 @@
 ;;; GNU Mes --- Maxwell Equations of Software
-;;; Copyright © 2016,2017,2018,2019,2020 Jan (janneke) Nieuwenhuizen <janneke@gnu.org>
+;;; Copyright © 2016,2017,2018,2019,2020,2021 Jan (janneke) Nieuwenhuizen <janneke@gnu.org>
 ;;;
 ;;; This file is part of GNU Mes.
 ;;;
@@ -359,10 +359,11 @@
 
 (define (arch-get-machine options)
   (let* ((machine (option-ref options 'machine #f))
-         (arch (option-ref options 'arch #f)))
-    (or machine
-        (if (member arch '("x86_64")) "64"
-            "32"))))
+         (arch (option-ref options 'arch #f))
+         (machine (or machine arch "32")))
+    (cond ((member machine '("x86_64")) "64")
+          ((member machine '("arm")) "32")
+          (else "32"))))
 
 (define (arch-get-m1-macros options)
   (let ((arch (arch-get options)))