diff --git a/util/check-sources.pl b/util/check-sources.pl
new file mode 100644
index 0000000000..be7f4b401c
--- /dev/null
+++ b/util/check-sources.pl
@@ -0,0 +1,255 @@
+#! /usr/bin/perl -ws
+#
+# Copyright (C) 2000  Internet Software Consortium.
+# 
+# Permission to use, copy, modify, and distribute this software for any
+# purpose with or without fee is hereby granted, provided that the above
+# copyright notice and this permission notice appear in all copies.
+# 
+# THE SOFTWARE IS PROVIDED "AS IS" AND INTERNET SOFTWARE CONSORTIUM DISCLAIMS
+# ALL WARRANTIES WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES
+# OF MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL INTERNET SOFTWARE
+# CONSORTIUM BE LIABLE FOR ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL
+# DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR
+# PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS
+# ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS
+# SOFTWARE.
+
+# Rudimentary, primarily for use by the developers.
+# This just evolved with no serious attempt at making it
+# bulletproof or foolproof.  Or pretty even.  Probably would
+# have done it differently if it were actually designed as opposed
+# to just growing as a multi-tentacled thing as various messages
+# were either added or selectively silenced.
+
+use strict;
+use vars qw($help $debug);
+
+sub
+sortdir() {
+  if (-d $::a) {
+    if (-d $::b) {
+      return ($::a cmp $::b);
+    } else {
+      return (-1);
+    }
+  } elsif (-d $::b) {
+    return (1);
+  } else {
+    return ($::a cmp $::b);
+  }
+}
+
+sub
+do_dir($$) {
+  my($predir, $dir) = @_;
+
+  my $newdir = $predir ne "" ? "$predir/$dir" : $dir;
+
+  print "================> $newdir\n";
+
+  unless (chdir("$dir")) {
+    print "cd $newdir: $1\n";
+    return;
+  }
+
+  unless (opendir(DIR, ".")) {
+    print "opendir $predir/$dir: $!\n";
+    return;
+  }
+
+  foreach my $entry (sort sortdir readdir(DIR)) {
+    next if $entry =~ /^\.\.?$/;
+
+    if (-d $entry) {
+      do_dir($newdir, $entry);
+      next;
+    }
+
+    next if $entry !~ /\.o$/;
+
+    do_file($entry);
+  }
+
+  closedir(DIR);
+
+  chdir("..") or
+    die "major malfunction: can't chdir to parent dir: $!\n";
+
+  print "================> $predir\n";
+}
+
+sub
+do_file($) {
+  my $objfile = $_[0];
+  my ($file, $savesource, $saveobj);
+  my ($config_h, $cpp_if, $prefix, $elided, $comment, $prefix_extend, $body);
+
+  unless ($objfile =~ /\.o$/) {
+    print "$0: skipping non-object file $objfile\n";
+    return;
+  }
+
+  ($file = $objfile) =~ s%\.o$%.c%;
+  ($savesource = $file) =~ s%$%.save%;
+  ($saveobj = $objfile) =~ s%$%.save%;
+
+  if (-f $savesource) {
+    print "$savesource exists, skipping\n";
+    return;
+  }
+
+  unless (-f $file) {
+    print "$file does not exist, skipping\n";
+    return;
+  }
+
+  rename($file, $savesource);
+  rename($objfile, $saveobj);
+
+  open(SOURCE, "< $savesource");
+  $_ = join('', <SOURCE>);
+  close(SOURCE);
+
+  $prefix = '';
+
+  print "$file begin\n" if $debug;
+
+  while (1) {
+    eval {
+      # Note that only '#include <...>' is checked, not '#include "..."'.
+      #     1             23         4            5      6      78
+      if (m%(\A\Q$prefix\E((.*\n)*?))(\#include\s+(<.*?>)(.*)\n)((.*\n)*)%) {
+        $elided = $5;
+        $prefix_extend = $2 . $4;
+        $comment = $6;
+        $body = $1 . $7;
+      } else {
+        print "$file end\n" if $debug;
+        $elided = "";           # stop processing this file.
+      }
+    };
+
+    if ($@ ne "") {
+      print "$file processing failed: $@\n";
+      last;
+    }
+
+    last if $elided eq "";
+
+    print STDERR "$file checking $elided\n" if $debug;
+
+    if (! $config_h) {
+      $config_h = 1;
+      if ($elided ne "<config.h>") {
+        print "$file should include <config.h> before any other\n";
+      }
+    }
+
+    # Always required.
+    next if $elided eq "<config.h>";
+
+    # Can mark in the header file when a #include should stay even
+    # though it might not appear that way otherwise.
+    next if $comment =~ /require|provide|extend|define|contract|explicit/i;
+
+    if ($elided eq "<isc/print.h>") {
+      next if m%snprintf%m;
+    }
+
+    open(SOURCE, "> $file");
+    print SOURCE "$body";
+    close(SOURCE);
+
+    print "$file elided $elided, compiling\n" if $debug;
+
+    if (compile($objfile) == 0) {
+      if (! defined($cpp_if)) {
+        $cpp_if = /^#if/m;
+        print "$file has CPP #if(def), doublecheck elision recommendations.\n"
+          if $cpp_if;
+      }
+      print "$file does not need $elided\n";
+    } elsif ($elided eq "<string.h>") {
+      print "$file prefer <isc/string.h> to <string.h>\n";
+    }
+
+  } continue {
+    $prefix .= $prefix_extend;
+  }
+
+  rename($savesource, $file);
+  rename($saveobj, $objfile);
+}
+
+sub
+compile($) {
+  my $obj = $_[0];
+
+  unless ($obj =~ /\.o$/) {
+    warn "$obj: not a .o object file\n";
+    return;
+  }
+
+  my $output = $debug ? "/dev/tty" : "/dev/null";
+
+  open(COMPILE, "make $obj 2>&1 >$output |");
+  my $stderr_lines = join('', <COMPILE>);
+  print $stderr_lines if $debug;
+  close(COMPILE);
+
+  unlink($obj);
+
+  return ($stderr_lines ne "");
+}
+
+sub
+main() {
+  $| = 1;
+
+  $0 =~ s%.*/%%;
+
+  die "Usage: $0 [-debug]\n" if $help;
+
+  unless (-f 'configure' && -f 'Makefile') {
+    die "$0: run from top of bind9 source tree, after configure has run\n";
+  }
+
+  print "========================\n";
+  print "building initial objects\n";
+  print "========================\n";
+
+  # XXX bleah
+  unless (system("make") == 0) {
+    die "make all failed, couldn't be sure all objects were generated.\n";
+  }
+
+  unless (system("cd bin/tests && make -k all_tests") == 0) {
+    warn "make all_tests failed, but pressging on anyway\n";
+  }
+
+  print <<EOF;
+================================================================
+                    starting header elision
+
+WARNING: Since this script only removes one header at a time,
+programs might compile fine without the header because another
+header provides the required information.  If that header is
+also recommend for removal, then removing both of them could
+lead to a program that does *not* compile fine.  So the only
+way to be sure is to take them all out and then recompile to
+see if there are any residual warnings/errors.
+
+Similar, this program is quite ignorant when it comes to CPP
+#if/#ifdef.  It might well be that a header file does not
+appear to be necessary because the code that depends on it
+is not being compiled.  To prevent this program from complaining
+about such includes in later runs, put a "Required for ..."
+comment on the same line as the #include.
+================================================================
+EOF
+
+  do_dir("", ".");
+}
+
+main();