diff --git a/bootstrap.conf b/bootstrap.conf
--- a/bootstrap.conf
+++ b/bootstrap.conf
@@ -173,6 +173,8 @@ SKIP_PO=true
 
 bootstrap_post_import_hook ()
 {
+  SHELL=${CONFIG_SHELL-/bin/sh}
+
   ## Check for files that automake --gnu would normally look for, except
   ## AUTHORS, which we autogenerate from the documentation files along
   ## with building the rest of Octave, and INSTALL, which is linked from
@@ -188,16 +190,16 @@ bootstrap_post_import_hook ()
   echo "generating source lists for liboctave/operators/module.mk..."
 
   rm -f liboctave/operators/*-op-*.mk
-  (cd liboctave/operators && ${SHELL:-/bin/sh} config-ops.sh)
+  (cd liboctave/operators && ${SHELL} config-ops.sh)
 
   echo "generating doc/interpreter/images.mk..."
 
   rm -f doc/interpreter/images.mk
-  (cd doc/interpreter && ${SHELL:-/bin/sh} config-images.sh)
+  (cd doc/interpreter && ${SHELL} config-images.sh)
 
   echo "generating libinterp/dldfcn/module.mk..."
 
   rm -f libinterp/dldfcn/module.mk
-  (cd libinterp/dldfcn && ${SHELL:-/bin/sh} config-module.sh)
+  (cd libinterp/dldfcn && ${SHELL} config-module.sh)
 }