Doc: Move root of code documentation to doc dir

C doc

D doc/prog-head.sgml

D doc/prog-intro.sgml

C nest

C conf

C filter

C proto

C sysdep

C lib

D doc/prog-foot.sgml

D prog-intro.sgml

$srcdir = $ARGV[0];

open(OUT, ">prog.sgml") || die "Cannot create output file";

include("doc/prog-head.sgml");

process("");

include("doc/prog-foot.sgml");

process("", "doc/prog-root");

close OUT;

exit 0;

sub process {

  my $dir = shift @_;

  print "$dir/progdoc\n";

  open(IN, "$srcdir/$dir/progdoc") || die "Unable to read $dir/progdoc";

  my $doc = "$dir/" . shift @_;

  print "$doc\n";

  open(IN, "$srcdir/$doc") || die "Unable to read $doc";

  my @docfile = <IN>;

  close IN;

  foreach $_ (@docfile) {

    /^([A-Z]+)\s*(.*)/ || die "Parse error: $_";

    $cmd = $1;

    $arg = $2;

    if ($cmd eq "C") { process("$dir/$arg"); }

    if ($cmd eq "C") { process("$dir/$arg", "progdoc"); }

    elsif ($cmd eq "H") {

      push @stack, "H";

      print OUT "<chapt>$arg\n";