-exec /usr/bin/perl -e '$|=1; while (<>) {
-'"` (cd "$DIR_AD";m4 -P main)|awk '/./{print "s@^http://"$0".*$@http://localhost/cgi-bin/redirector-ad.cgi?"$0"@;"}' `"'
-print; }'
+use re 'eval';
+
+my $DIR_AD=dirname($0)."/ad";
+
+
+chdir $DIR_AD or die "chdir $DIR_AD: $!";
+select STDOUT;
+$|=1;
+my @got;
+
+RELOAD: {
+ my $patt="";
+ open(M4,"-|","m4 --prefix-builtins --synclines main") or die "m4 run: $!";
+ my %files;
+ while (<M4>) {
+ chomp;
+ next if !$_;
+ do { $files{$1}=undef; next; } if /^#\s*line\s+\d+\s+"(.*)"$/;
+ $patt.="|" if $patt;
+ $patt.=$_."(?{ '";
+ s/'/'."'".'/g;
+ $patt.="$_'; })";
+ }
+ close M4;
+ $patt=qr @^http://($patt).*\n$@;
+
+ while ($_=shift @got || <>) {
+ while (my($file,$old)=each %files) {
+ my $new=(stat $file)[9];
+ $files{$file}=$new;
+ next if !defined $old || $old==$new;
+ push @got,$_;
+ redo RELOAD;
+ }
+ s@$patt@http://localhost/cgi-bin/redirector-ad.cgi?$^R\n@;
+ print;
+ }
+ } # RELOAD