diff --git a/tools/mkdep.pl b/tools/mkdep.pl
index 3c1b6acb..44ed0f68 100755
--- a/tools/mkdep.pl
+++ b/tools/mkdep.pl
@@ -52,6 +52,7 @@ my $barrier =
     "#-- Everything below is generated by mkdep.pl - do not edit --#\n";
 
 # This converts from filenames to full pathnames for our dependencies
+# These are arrays of [full path, Makefile path]
 my %dep_path = ();
 
 # List of files that cannot be found; these *must* be excluded
@@ -73,16 +74,21 @@ my $debug = 0;
 
 #
 # Scan files for dependencies
+# $path is the full filesystem path, $file Makefile name
 #
 sub scandeps {
-    # path is the filesystem path, file what the output should call it
     my($path, $file) = @_;
     my $line;
     my %xdeps;
     my %mdeps;
 
-    open(my $fh, '<', $path)
-	or return;		# If not openable, assume generated
+    print STDERR "mkdep: scanning file: $path\n" if ( $debug );
+
+    my $fh;
+    if (!open($fh, '<', $path)) {
+	print STDERR "    -> missing, assume generated\n" if ( $debug );
+	return;
+    }
 
     while ( defined($line = <$fh>) ) {
 	chomp $line;
@@ -90,35 +96,46 @@ sub scandeps {
 	$line =~ s://.*$::;
 	if ( $line =~ /^\s*\#\s*include\s+\"(.*)\"\s*$/ ) {
 	    my $nf = $1;
-	    if (!defined($dep_path{$nf})) {
+	    my $dp = $dep_path{$nf};
+	    if (!defined($dp)) {
 		push(@must_exclude, $nf);
+		print STDERR "    -> $nf [missing]\n" if ( $debug );
 		next;
 	    }
-	    $nf = $dep_path{$nf};
-	    $mdeps{$nf}++;
-	    $xdeps{$nf}++ unless ( defined($deps{$nf}) );
+	    my $dn = $dp->[1];
+	    $mdeps{$dn}++;
+	    $xdeps{$dn} = $dp unless ( defined($deps{$dn}) );
+	    printf STDERR "    -> %s (%s)\n", $nf, $dn if ( $debug );
 	}
     }
     close($fh);
     $deps{$file} = [keys(%mdeps)];
 
     foreach my $xf ( keys(%xdeps) ) {
-	scandeps($xf);
+	scandeps(@{$xdeps{$xf}});
     }
 }
 
 # %deps contains direct dependencies.  This subroutine resolves
 # indirect dependencies that result.
-sub alldeps($$) {
-    my($file, $level) = @_;
-    my %adeps;
+sub _alldeps($$$) {
+    my($file, $level, $adeps) = @_;
+
+    return if ($adeps->{$file});
+
+    printf STDERR " %s-> %s\n", ('   ' x $level), $file;
+    $adeps->{$file}++;
 
     foreach my $dep ( @{$deps{$file}} ) {
-	$adeps{$dep} = 1;
-	foreach my $idep ( alldeps($dep, $level+1) ) {
-	    $adeps{$idep} = 1;
-	}
+	_alldeps($dep, $level+1, $adeps);
     }
+}
+
+sub alldeps($) {
+    my($file) = @_;
+
+    my %adeps;
+    _alldeps($file, 1, \%adeps);
     return sort(keys(%adeps));
 }
 
@@ -177,7 +194,7 @@ sub insert_deps($) {
 	    my $fpath = $1;
 	    my $fbase = basename($fpath);
 	    if (!defined($dep_path{$fbase})) {
-		$dep_path{$fbase} = $fpath;
+		$dep_path{$fbase} = [$fpath, $fpath];
 		print STDERR "Makefile: $fbase -> $fpath\n";
 	    }
 	} elsif ( $line =~ /^\s*\#\s*@([a-z0-9-]+):\s*\"([^\"]*)\"/ ) {
@@ -249,7 +266,8 @@ sub insert_deps($) {
 		@deps = sort(keys(%deps));
 	    } elsif ( $dfile =~ /^(.*)\.[Cc]$/ ) {
 		$ofile = convert_file($1, $sep).$obj.':';
-		@deps = ($dfile,alldeps($dfile,1));
+		print STDERR "mkdep: dependencies for: $dfile\n";
+		@deps = alldeps($dfile);
 	    }
 
 	    if (defined($ofile)) {
@@ -332,12 +350,15 @@ foreach my $fdir ( @files ) {
 
     foreach my $sdir ( @searchdirs ) {
 	my $dir = mycatdir($sdir, $fdir);
+
 	if ($scanned{$dir}) {
 	    # Have already been here
 	    $found = 1;
 	    next;
 	}
 
+	print STDERR "mkdep: scanning directory $dir\n" if ( $debug );
+
 	opendir(DIR, $dir) or next;
 	$scanned{$dir}++;
 	$found++;
@@ -351,9 +372,12 @@ foreach my $fdir ( @files ) {
 	    if ( $file =~ /\.[Cc]$/ ) {
 		push(@cfiles, [$fullpath, $path]);
 	    } elsif ( $file =~ /\.[Hh]$/ ) {
-		print STDERR "Filesystem: $file -> $path\n" if ( $debug );
-		$dep_path{$file} = $path; # Allow the blank filename
-		$dep_path{$path} = $path; # Also allow the full pathname
+		print STDERR "mkdep: filesystem: $file -> $path\n" if ( $debug );
+		if (defined($dep_path{$file})) {
+		    print STDERR "mkdep: warning: more than one instance of filename $file!\n";
+		}
+		$dep_path{$file} = [$fullpath, $path];
+		$dep_path{$path} = [$fullpath, $path];
 	    }
 	}
 	closedir(DIR);