diff --git a/bootstrap b/bootstrap
line changes: +39/-22
index 282c677..932ff85
--- a/bootstrap
+++ b/bootstrap

@@ -1,11 +1,10 @@
 #! /bin/sh
 # Print a version string.
-scriptversion=2013-12-05.23; # UTC
+scriptversion=2017-01-09.19; # UTC
 
 # Bootstrap this package from checked-out sources.
 
-# Copyright (C) 2003, 2004, 2005, 2006, 2007, 2008, 2009, 2010, 2011,
-# 2012, 2013, 2014, 2015 Free Software Foundation, Inc.
+# Copyright (C) 2003-2017 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

@@ -43,6 +42,9 @@ export LC_ALL
 
 local_gl_dir=gl
 
+# Honor $PERL, but work even if there is none.
+PERL="${PERL-perl}"
+
 me=$0
 
 usage() {

@@ -416,28 +418,30 @@ sort_ver() { # sort -V is not generally available
   done
 }
 
-get_version() {
-  app=$1
+get_version_sed='
+# Move version to start of line.
+s/.*[v ]\([0-9]\)/\1/
 
-  $app --version >/dev/null 2>&1 || { $app --version; return 1; }
+# Skip lines that do not start with version.
+/^[0-9]/!d
+
+# Remove characters after the version.
+s/[^.a-z0-9-].*//
 
-  $app --version 2>&1 |
-  sed -n '# Move version to start of line.
-          s/.*[v ]\([0-9]\)/\1/
+# The first component must be digits only.
+s/^\([0-9]*\)[a-z-].*/\1/
 
-          # Skip lines that do not start with version.
-          /^[0-9]/!d
+#the following essentially does s/5.005/5.5/
+s/\.0*\([1-9]\)/.\1/g
+p
+q'
 
-          # Remove characters after the version.
-          s/[^.a-z0-9-].*//
+get_version() {
+  app=$1
 
-          # The first component must be digits only.
-          s/^\([0-9]*\)[a-z-].*/\1/
+  $app --version >/dev/null 2>&1 || { $app --version; return 1; }
 
-          #the following essentially does s/5.005/5.5/
-          s/\.0*\([1-9]\)/.\1/g
-          p
-          q'
+  $app --version 2>&1 | sed -n "$get_version_sed"
 }
 
 check_versions() {

@@ -457,6 +461,7 @@ check_versions() {
     test "$appvar" = TAR && appvar=AMTAR
     case $appvar in
         GZIP) ;; # Do not use $GZIP:  it contains gzip options.
+        PERL::*) ;; # Keep perl modules as-is
         *) eval "app=\${$appvar-$app}" ;;
     esac
 

@@ -474,6 +479,17 @@ check_versions() {
           ret=1
           continue
         } ;;
+      # Another check is for perl modules.  These can be written as
+      # e.g. perl::XML::XPath in case of XML::XPath module, etc.
+      perl::*)
+        # Extract module name
+        app="${app#perl::}"
+        if ! $PERL -m"$app" -e 'exit 0' >/dev/null 2>&1; then
+          warn_ "Error: perl module '$app' not found"
+          ret=1
+        fi
+        continue
+        ;;
     esac
     if [ "$req_ver" = "-" ]; then
       # Merely require app to exist; not all prereq apps are well-behaved

@@ -774,7 +790,7 @@ symlink_to_dir()
       # Leave any existing symlink alone, if it already points to the source,
       # so that broken build tools that care about symlink times
       # aren't confused into doing unnecessary builds.  Conversely, if the
-      # existing symlink's time stamp is older than the source, make it afresh,
+      # existing symlink's timestamp is older than the source, make it afresh,
       # so that broken tools aren't confused into skipping needed builds.  See
       # <http://lists.gnu.org/archive/html/bug-gnulib/2011-05/msg00326.html>.
       test -h "$dst" &&

@@ -901,7 +917,8 @@ if test $use_libtool = 1; then
   esac
 fi
 echo "$0: $gnulib_tool $gnulib_tool_options --import ..."
-$gnulib_tool $gnulib_tool_options --import $gnulib_modules &&
+$gnulib_tool $gnulib_tool_options --import $gnulib_modules \
+  || die "gnulib-tool failed"
 
 for file in $gnulib_files; do
   symlink_to_dir "$GNULIB_SRCDIR" $file \

@@ -1006,6 +1023,6 @@ echo "$0: done.  Now you can run './configure'."
 # eval: (add-hook 'write-file-hooks 'time-stamp)
 # time-stamp-start: "scriptversion="
 # time-stamp-format: "%:y-%02m-%02d.%02H"
-# time-stamp-time-zone: "UTC"
+# time-stamp-time-zone: "UTC0"
 # time-stamp-end: "; # UTC"
 # End:

diff --git a/bootstrap.conf b/bootstrap.conf
line changes: +4/-5
index 3f0cc1d..262b373
--- a/bootstrap.conf
+++ b/bootstrap.conf

@@ -1,7 +1,6 @@
 # Bootstrap configuration.
 
-# Copyright (C) 2006, 2007, 2008, 2009, 2010, 2011, 2012, 2013, 2014,
-# 2015 Free Software Foundation, Inc.
+# Copyright (C) 2006-2017 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

@@ -111,9 +110,9 @@ bootstrap_epilogue()
     hooks=$(cd scripts/git-hooks && git ls-files)
     for f in $hooks; do
       if [ -f .git/hooks/$f ]; then
-	# If it is identical, skip it.
-	cmp scripts/git-hooks/$f .git/hooks/$f > /dev/null \
-	  && continue
+       # If it is identical, skip it.
+       cmp scripts/git-hooks/$f .git/hooks/$f > /dev/null \
+	 && continue
       fi
       cp --backup=numbered scripts/git-hooks/$f .git/hooks
       chmod a-w .git/hooks/$f

diff --git a/build-aux/git-version-gen b/build-aux/git-version-gen
line changes: +10/-10
index d516393..079849d
--- a/build-aux/git-version-gen
+++ b/build-aux/git-version-gen

@@ -1,9 +1,8 @@
 #!/bin/sh
 # Print a version string.
-scriptversion=2012-12-31.23; # UTC
+scriptversion=2017-01-09.19; # UTC
 
-# Copyright (C) 2007, 2008, 2009, 2010, 2011, 2012, 2013, 2014, 2015
-# Free Software Foundation, Inc.
+# Copyright (C) 2007-2017 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

@@ -86,8 +85,9 @@ Print a version string.
 
 Options:
 
-   --prefix           prefix of git tags (default 'v')
-   --fallback         fallback version to use if \"git --version\" fails
+   --prefix PREFIX    prefix of git tags (default 'v')
+   --fallback VERSION
+                      fallback version to use if \"git --version\" fails
 
    --help             display this help and exit
    --version          output version information and exit

@@ -101,8 +101,8 @@ while test $# -gt 0; do
   case $1 in
     --help) echo "$usage"; exit 0;;
     --version) echo "$version"; exit 0;;
-    --prefix) shift; prefix="$1";;
-    --fallback) shift; fallback="$1";;
+    --prefix) shift; prefix=${1?};;
+    --fallback) shift; fallback=${1?};;
     -*)
       echo "$0: Unknown option '$1'." >&2
       echo "$0: Try '--help' for more information." >&2

@@ -200,7 +200,7 @@ v=`echo "$v" |sed "s/^$prefix//"`
 # string we're using came from git.  I.e., skip the test if it's "UNKNOWN"
 # or if it came from .tarball-version.
 if test "x$v_from_git" != x; then
-  # Don't declare a version "dirty" merely because a time stamp has changed.
+  # Don't declare a version "dirty" merely because a timestamp has changed.
   git update-index --refresh > /dev/null 2>&1
 
   dirty=`exec 2>/dev/null;git diff-index --name-only HEAD` || dirty=

@@ -215,12 +215,12 @@ if test "x$v_from_git" != x; then
 fi
 
 # Omit the trailing newline, so that m4_esyscmd can use the result directly.
-echo "$v" | tr -d "$nl"
+printf %s "$v"
 
 # Local variables:
 # eval: (add-hook 'write-file-hooks 'time-stamp)
 # time-stamp-start: "scriptversion="
 # time-stamp-format: "%:y-%02m-%02d.%02H"
-# time-stamp-time-zone: "UTC"
+# time-stamp-time-zone: "UTC0"
 # time-stamp-end: "; # UTC"
 # End: