diff --git a/bootstrap b/bootstrap
index 8f76d696..7523f65b 100755
--- a/bootstrap
+++ b/bootstrap
@@ -1,10 +1,10 @@
 #! /bin/sh
 # Print a version string.
-scriptversion=2020-04-13.15; # UTC
+scriptversion=2020-11-18.17; # UTC
 
 # Bootstrap this package from checked-out sources.
 
-# Copyright (C) 2003-2020 Free Software Foundation, Inc.
+# Copyright (C) 2003-2021 Free Software Foundation, Inc.
 
 # This program is free software: you can redistribute it and/or modify
 # it under the terms of the GNU General Public License as published by
@@ -71,7 +71,9 @@ Options:
  --no-git                 do not use git to update gnulib.  Requires that
                           --gnulib-srcdir point to a correct gnulib snapshot
  --skip-po                do not download po files
-
+EOF
+  bootstrap_print_option_usage_hook
+  cat <<EOF
 If the file $me.conf exists in the same directory as this script, its
 contents are read as shell variables to configure the bootstrap.
 
@@ -154,6 +156,18 @@ gnulib_files=
 : ${AUTOPOINT=autopoint}
 : ${AUTORECONF=autoreconf}
 
+# A function to be called for each unrecognized option.  Returns 0 if
+# the option in $1 has been processed by the function.  Returns 1 if
+# the option has not been processed by the function.  Override it via
+# your own definition in bootstrap.conf
+
+bootstrap_option_hook() { return 1; }
+
+# A function to be called in order to print the --help information
+# corresponding to user-defined command-line options.
+
+bootstrap_print_option_usage_hook() { :; }
+
 # A function to be called right after gnulib-tool is run.
 # Override it via your own definition in bootstrap.conf.
 bootstrap_post_import_hook() { :; }
@@ -335,7 +349,7 @@ do
   --no-git)
     use_git=false;;
   *)
-    die "$option: unknown option";;
+    bootstrap_option_hook $option || die "$option: unknown option";;
   esac
 done
 
diff --git a/gnulib b/gnulib
index a5578a71..bb6ecf32 160000
--- a/gnulib
+++ b/gnulib
@@ -1 +1 @@
-Subproject commit a5578a71ef65a9aed1ccc254b9d9a07b0b46c1b0
+Subproject commit bb6ecf3278cce40cfa6be693697e7995dca1a038
diff --git a/tests/init.sh b/tests/init.sh
index b4a5944a..9ef83488 100755
--- a/tests/init.sh
+++ b/tests/init.sh
@@ -1,6 +1,6 @@
 # source this file; set up for tests
 
-# Copyright (C) 2009-2020 Free Software Foundation, Inc.
+# Copyright (C) 2009-2021 Free Software Foundation, Inc.
 
 # This program is free software: you can redistribute it and/or modify
 # it under the terms of the GNU General Public License as published by
@@ -389,7 +389,7 @@ setup_ ()
   if test "$VERBOSE" = yes; then
     # Test whether set -x may cause the selected shell to corrupt an
     # application's stderr.  Many do, including zsh-4.3.10 and the /bin/sh
-    # from SunOS 5.11, OpenBSD 4.7 and Irix 5.x and 6.5.
+    # from SunOS 5.11, OpenBSD 4.7 and Irix 6.5.
     # If enabling verbose output this way would cause trouble, simply
     # issue a warning and refrain.
     if $gl_set_x_corrupts_stderr_; then