diff --git a/bootstrap b/bootstrap
index 246310e..5264d9f 100755
--- a/bootstrap
+++ b/bootstrap
@@ -1,6 +1,6 @@
 #! /bin/sh
 # Print a version string.
-scriptversion=2018-01-07.00; # UTC
+scriptversion=2018-10-13.05; # UTC
 
 # Bootstrap this package from checked-out sources.
 
@@ -47,6 +47,8 @@ PERL="${PERL-perl}"
 
 me=$0
 
+default_gnulib_url=git://git.sv.gnu.org/gnulib
+
 usage() {
   cat <<EOF
 Usage: $me [OPTION]...
@@ -76,6 +78,37 @@ contents are read as shell variables to configure the bootstrap.
 For build prerequisites, environment variables like \$AUTOCONF and \$AMTAR
 are honored.
 
+Gnulib sources can be fetched in various ways:
+
+ * If this package is in a git repository with a 'gnulib' submodule
+   configured, then that submodule is initialized and updated and sources
+   are fetched from there.  If \$GNULIB_SRCDIR is set (directly or via
+   --gnulib-srcdir) and is a git repository, then it is used as a reference.
+
+ * Otherwise, if \$GNULIB_SRCDIR is set (directly or via --gnulib-srcdir),
+   then sources are fetched from that local directory.  If it is a git
+   repository and \$GNULIB_REVISION is set, then that revision is checked
+   out.
+
+ * Otherwise, if this package is in a git repository with a 'gnulib'
+   submodule configured, then that submodule is initialized and updated and
+   sources are fetched from there.
+
+ * Otherwise, if the 'gnulib' directory does not exist, Gnulib sources are
+   cloned into that directory using git from \$GNULIB_URL, defaulting to
+   $default_gnulib_url.
+   If \$GNULIB_REVISION is set, then that revision is checked out.
+
+ * Otherwise, the existing Gnulib sources in the 'gnulib' directory are
+   used.  If it is a git repository and \$GNULIB_REVISION is set, then that
+   revision is checked out.
+
+If you maintain a package and want to pin a particular revision of the
+Gnulib sources that has been tested with your package, then there are two
+possible approaches: either configure a 'gnulib' submodule with the
+appropriate revision, or set \$GNULIB_REVISION (and if necessary
+\$GNULIB_URL) in $me.conf.
+
 Running without arguments will suffice in most cases.
 EOF
 }
@@ -129,18 +162,11 @@ bootstrap_post_import_hook() { :; }
 # Override it via your own definition in bootstrap.conf.
 bootstrap_epilogue() { :; }
 
-# The command to download all .po files for a specified domain into
-# a specified directory.  Fill in the first %s is the domain name, and
-# the second with the destination directory.  Use rsync's -L and -r
-# options because the latest/%s directory and the .po files within are
-# all symlinks.
+# The command to download all .po files for a specified domain into a
+# specified directory.  Fill in the first %s with the destination
+# directory and the second with the domain name.
 po_download_command_format=\
-"rsync --delete --exclude '*.s1' -Lrtvz \
- 'translationproject.org::tp/latest/%s/' '%s'"
-
-# Fallback for downloading .po files (if rsync fails).
-po_download_command_format2=\
-"wget --mirror -nd -q -np -A.po -P '%s' \
+"wget --mirror --level=1 -nd -q -A.po -P '%s' \
  https://translationproject.org/latest/%s/"
 
 # Prefer a non-empty tarname (4th argument of AC_INIT if given), else
@@ -170,7 +196,15 @@ source_base=lib
 m4_base=m4
 doc_base=doc
 tests_base=tests
-gnulib_extra_files=''
+gnulib_extra_files="
+        build-aux/install-sh
+        build-aux/mdate-sh
+        build-aux/texinfo.tex
+        build-aux/depcomp
+        build-aux/config.guess
+        build-aux/config.sub
+        doc/INSTALL
+"
 
 # Additional gnulib-tool options to use.  Use "\newline" to break lines.
 gnulib_tool_option_extras=
@@ -264,24 +298,18 @@ case "$0" in
   *) test -r "$0.conf" && . ./"$0.conf" ;;
 esac
 
-# Extra files from gnulib, which override files from other sources.
-test -z "${gnulib_extra_files}" && \
-  gnulib_extra_files="
-        build-aux/install-sh
-        build-aux/mdate-sh
-        build-aux/texinfo.tex
-        build-aux/depcomp
-        build-aux/config.guess
-        build-aux/config.sub
-        doc/INSTALL
-"
-
 if test "$vc_ignore" = auto; then
   vc_ignore=
   test -d .git && vc_ignore=.gitignore
   test -d CVS && vc_ignore="$vc_ignore .cvsignore"
 fi
 
+if test x"$gnulib_modules$gnulib_files$gnulib_extra_files" = x; then
+  use_gnulib=false
+else
+  use_gnulib=true
+fi
+
 # Translate configuration into internal form.
 
 # Parse options.
@@ -612,95 +640,101 @@ git_modules_config () {
   test -f .gitmodules && git config --file .gitmodules "$@"
 }
 
-if $use_git; then
-  gnulib_path=$(git_modules_config submodule.gnulib.path)
-  test -z "$gnulib_path" && gnulib_path=gnulib
-fi
-
-# Get gnulib files.  Populate $GNULIB_SRCDIR, possibly updating a
-# submodule, for use in the rest of the script.
-
-case ${GNULIB_SRCDIR--} in
--)
-  # Note that $use_git is necessarily true in this case.
-  if git_modules_config submodule.gnulib.url >/dev/null; then
-    echo "$0: getting gnulib files..."
-    git submodule init -- "$gnulib_path" || exit $?
-    git submodule update -- "$gnulib_path" || exit $?
-
-  elif [ ! -d "$gnulib_path" ]; then
-    echo "$0: getting gnulib files..."
-
-    trap cleanup_gnulib 1 2 13 15
-
-    shallow=
-    git clone -h 2>&1 | grep -- --depth > /dev/null && shallow='--depth 2'
-    git clone $shallow git://git.sv.gnu.org/gnulib "$gnulib_path" ||
-      cleanup_gnulib
-
-    trap - 1 2 13 15
+if $use_gnulib; then
+  if $use_git; then
+    gnulib_path=$(git_modules_config submodule.gnulib.path)
+    test -z "$gnulib_path" && gnulib_path=gnulib
   fi
-  GNULIB_SRCDIR=$gnulib_path
-  ;;
-*)
-  # Use GNULIB_SRCDIR directly or as a reference.
-  if $use_git && test -d "$GNULIB_SRCDIR"/.git && \
-        git_modules_config submodule.gnulib.url >/dev/null; then
-    echo "$0: getting gnulib files..."
-    if git submodule -h|grep -- --reference > /dev/null; then
-      # Prefer the one-liner available in git 1.6.4 or newer.
-      git submodule update --init --reference "$GNULIB_SRCDIR" \
-        "$gnulib_path" || exit $?
-    else
-      # This fallback allows at least git 1.5.5.
-      if test -f "$gnulib_path"/gnulib-tool; then
-        # Since file already exists, assume submodule init already complete.
-        git submodule update -- "$gnulib_path" || exit $?
-      else
-        # Older git can't clone into an empty directory.
-        rmdir "$gnulib_path" 2>/dev/null
-        git clone --reference "$GNULIB_SRCDIR" \
-          "$(git_modules_config submodule.gnulib.url)" "$gnulib_path" \
-          && git submodule init -- "$gnulib_path" \
-          && git submodule update -- "$gnulib_path" \
-          || exit $?
+
+  # Get gnulib files.  Populate $GNULIB_SRCDIR, possibly updating a
+  # submodule, for use in the rest of the script.
+
+  case ${GNULIB_SRCDIR--} in
+  -)
+    # Note that $use_git is necessarily true in this case.
+    if git_modules_config submodule.gnulib.url >/dev/null; then
+      echo "$0: getting gnulib files..."
+      git submodule init -- "$gnulib_path" || exit $?
+      git submodule update -- "$gnulib_path" || exit $?
+
+    elif [ ! -d "$gnulib_path" ]; then
+      echo "$0: getting gnulib files..."
+
+      trap cleanup_gnulib 1 2 13 15
+
+      shallow=
+      if test -z "$GNULIB_REVISION"; then
+        git clone -h 2>&1 | grep -- --depth > /dev/null && shallow='--depth 2'
       fi
+      git clone $shallow ${GNULIB_URL:-$default_gnulib_url} "$gnulib_path" \
+        || cleanup_gnulib
+
+      trap - 1 2 13 15
     fi
     GNULIB_SRCDIR=$gnulib_path
+    ;;
+  *)
+    # Use GNULIB_SRCDIR directly or as a reference.
+    if $use_git && test -d "$GNULIB_SRCDIR"/.git && \
+          git_modules_config submodule.gnulib.url >/dev/null; then
+      echo "$0: getting gnulib files..."
+      if git submodule -h|grep -- --reference > /dev/null; then
+        # Prefer the one-liner available in git 1.6.4 or newer.
+        git submodule update --init --reference "$GNULIB_SRCDIR" \
+          "$gnulib_path" || exit $?
+      else
+        # This fallback allows at least git 1.5.5.
+        if test -f "$gnulib_path"/gnulib-tool; then
+          # Since file already exists, assume submodule init already complete.
+          git submodule update -- "$gnulib_path" || exit $?
+        else
+          # Older git can't clone into an empty directory.
+          rmdir "$gnulib_path" 2>/dev/null
+          git clone --reference "$GNULIB_SRCDIR" \
+            "$(git_modules_config submodule.gnulib.url)" "$gnulib_path" \
+            && git submodule init -- "$gnulib_path" \
+            && git submodule update -- "$gnulib_path" \
+            || exit $?
+        fi
+      fi
+      GNULIB_SRCDIR=$gnulib_path
+    fi
+    ;;
+  esac
+
+  if test -d "$GNULIB_SRCDIR"/.git && test -n "$GNULIB_REVISION" \
+     && ! git_modules_config submodule.gnulib.url >/dev/null; then
+    (cd "$GNULIB_SRCDIR" && git checkout "$GNULIB_REVISION") || cleanup_gnulib
   fi
-  ;;
-esac
 
-# $GNULIB_SRCDIR now points to the version of gnulib to use, and
-# we no longer need to use git or $gnulib_path below here.
+  # $GNULIB_SRCDIR now points to the version of gnulib to use, and
+  # we no longer need to use git or $gnulib_path below here.
 
-if $bootstrap_sync; then
-  cmp -s "$0" "$GNULIB_SRCDIR/build-aux/bootstrap" || {
-    echo "$0: updating bootstrap and restarting..."
-    case $(sh -c 'echo "$1"' -- a) in
-      a) ignored=--;;
-      *) ignored=ignored;;
-    esac
-    exec sh -c \
-      'cp "$1" "$2" && shift && exec "${CONFIG_SHELL-/bin/sh}" "$@"' \
-      $ignored "$GNULIB_SRCDIR/build-aux/bootstrap" \
-      "$0" "$@" --no-bootstrap-sync
-  }
+  if $bootstrap_sync; then
+    cmp -s "$0" "$GNULIB_SRCDIR/build-aux/bootstrap" || {
+      echo "$0: updating bootstrap and restarting..."
+      case $(sh -c 'echo "$1"' -- a) in
+        a) ignored=--;;
+        *) ignored=ignored;;
+      esac
+      exec sh -c \
+        'cp "$1" "$2" && shift && exec "${CONFIG_SHELL-/bin/sh}" "$@"' \
+        $ignored "$GNULIB_SRCDIR/build-aux/bootstrap" \
+        "$0" "$@" --no-bootstrap-sync
+    }
+  fi
+
+  gnulib_tool=$GNULIB_SRCDIR/gnulib-tool
+  <$gnulib_tool || exit $?
 fi
 
-gnulib_tool=$GNULIB_SRCDIR/gnulib-tool
-<$gnulib_tool || exit $?
-
 # Get translations.
 
 download_po_files() {
   subdir=$1
   domain=$2
   echo "$me: getting translations into $subdir for $domain..."
-  cmd=$(printf "$po_download_command_format" "$domain" "$subdir")
-  eval "$cmd" && return
-  # Fallback to HTTPS.
-  cmd=$(printf "$po_download_command_format2" "$subdir" "$domain")
+  cmd=$(printf "$po_download_command_format" "$subdir" "$domain")
   eval "$cmd"
 }
 
@@ -898,32 +932,33 @@ fi
 
 # Import from gnulib.
 
-gnulib_tool_options="\
- --import\
- --no-changelog\
- --aux-dir $build_aux\
- --doc-base $doc_base\
- --lib $gnulib_name\
- --m4-base $m4_base/\
- --source-base $source_base/\
- --tests-base $tests_base\
- --local-dir $local_gl_dir\
- $gnulib_tool_option_extras\
-"
-if test $use_libtool = 1; then
-  case "$gnulib_tool_options " in
-    *' --libtool '*) ;;
-    *) gnulib_tool_options="$gnulib_tool_options --libtool" ;;
-  esac
-fi
-echo "$0: $gnulib_tool $gnulib_tool_options --import ..."
-$gnulib_tool $gnulib_tool_options --import $gnulib_modules \
-  || die "gnulib-tool failed"
+if $use_gnulib; then
+  gnulib_tool_options="\
+   --no-changelog\
+   --aux-dir=$build_aux\
+   --doc-base=$doc_base\
+   --lib=$gnulib_name\
+   --m4-base=$m4_base/\
+   --source-base=$source_base/\
+   --tests-base=$tests_base\
+   --local-dir=$local_gl_dir\
+   $gnulib_tool_option_extras\
+  "
+  if test $use_libtool = 1; then
+    case "$gnulib_tool_options " in
+      *' --libtool '*) ;;
+      *) gnulib_tool_options="$gnulib_tool_options --libtool" ;;
+    esac
+  fi
+  echo "$0: $gnulib_tool $gnulib_tool_options --import ..."
+  $gnulib_tool $gnulib_tool_options --import $gnulib_modules \
+    || die "gnulib-tool failed"
 
-for file in $gnulib_files; do
-  symlink_to_dir "$GNULIB_SRCDIR" $file \
-    || die "failed to symlink $file"
-done
+  for file in $gnulib_files; do
+    symlink_to_dir "$GNULIB_SRCDIR" $file \
+      || die "failed to symlink $file"
+  done
+fi
 
 bootstrap_post_import_hook \
   || die "bootstrap_post_import_hook failed"
@@ -1020,7 +1055,7 @@ bootstrap_epilogue
 echo "$0: done.  Now you can run './configure'."
 
 # Local variables:
-# eval: (add-hook 'write-file-hooks 'time-stamp)
+# eval: (add-hook 'before-save-hook 'time-stamp)
 # time-stamp-start: "scriptversion="
 # time-stamp-format: "%:y-%02m-%02d.%02H"
 # time-stamp-time-zone: "UTC0"
diff --git a/gnulib b/gnulib
index b4f88b3..95c96b6 160000
--- a/gnulib
+++ b/gnulib
@@ -1 +1 @@
-Subproject commit b4f88b3c1163e6cbc6f63b76ee9f002d701031ed
+Subproject commit 95c96b6dddd31f3676f72ed044d0c493ab5642d8
diff --git a/tests/init.sh b/tests/init.sh
index 705a698..93d14f5 100644
--- a/tests/init.sh
+++ b/tests/init.sh
@@ -13,7 +13,7 @@
 # GNU General Public License for more details.
 
 # You should have received a copy of the GNU General Public License
-# along with this program.  If not, see <http://www.gnu.org/licenses/>.
+# along with this program.  If not, see <https://www.gnu.org/licenses/>.
 
 # Using this file in a test
 # =========================
@@ -62,6 +62,19 @@
 
 ME_=`expr "./$0" : '.*/\(.*\)$'`
 
+# Prepare PATH_SEPARATOR.
+# The user is always right.
+if test "${PATH_SEPARATOR+set}" != set; then
+  # Determine PATH_SEPARATOR by trying to find /bin/sh in a PATH which
+  # contains only /bin. Note that ksh looks also at the FPATH variable,
+  # so we have to set that as well for the test.
+  PATH_SEPARATOR=:
+  (PATH='/bin;/bin'; FPATH=$PATH; sh -c :) >/dev/null 2>&1 \
+    && { (PATH='/bin:/bin'; FPATH=$PATH; sh -c :) >/dev/null 2>&1 \
+           || PATH_SEPARATOR=';'
+       }
+fi
+
 # We use a trap below for cleanup.  This requires us to go through
 # hoops to get the right exit status transported through the handler.
 # So use 'Exit STATUS' instead of 'exit STATUS' inside of the tests.
@@ -250,7 +263,7 @@ test -n "$BASH_VERSION" && unalias -a
 # That is part of the shell-selection test above.  Why use aliases rather
 # than functions?  Because support for hyphen-containing aliases is more
 # widespread than that for hyphen-containing function names.
-test -n "$EXEEXT" && shopt -s expand_aliases
+test -n "$EXEEXT" && test -n "$BASH_VERSION" && shopt -s expand_aliases
 
 # Enable glibc's malloc-perturbing option.
 # This is useful for exposing code that depends on the fact that
@@ -429,13 +442,13 @@ path_prepend_ ()
     path_dir_=$1
     case $path_dir_ in
       '') fail_ "invalid path dir: '$1'";;
-      /*) abs_path_dir_=$path_dir_;;
+      /* | ?:*) abs_path_dir_=$path_dir_;;
       *) abs_path_dir_=$initial_cwd_/$path_dir_;;
     esac
     case $abs_path_dir_ in
-      *:*) fail_ "invalid path dir: '$abs_path_dir_'";;
+      *$PATH_SEPARATOR*) fail_ "invalid path dir: '$abs_path_dir_'";;
     esac
-    PATH="$abs_path_dir_:$PATH"
+    PATH="$abs_path_dir_$PATH_SEPARATOR$PATH"
 
     # Create an alias, FOO, for each FOO.exe in this directory.
     create_exe_shims_ "$abs_path_dir_" \
@@ -514,7 +527,7 @@ rand_bytes_ ()
   fi
 
   n_plus_50_=`expr $n_ + 50`
-  cmds_='date; date +%N; free; who -a; w; ps auxww; ps ef; netstat -n'
+  cmds_='date; date +%N; free; who -a; w; ps auxww; ps -ef'
   data_=` (eval "$cmds_") 2>&1 | gzip `
 
   # Ensure that $data_ has length at least 50+$n_