Don't rely on Architecture field in indextargets output because it's only filled for non-flat mirrors

mmdebstrap

@@ -715,7 +715,7 @@ sub setup {
     # Same if we want to install priority based variants.
     if ($options->{variant} ne 'apt') {
 	my %ess_pkgs;
-	open(my $pipe_apt, '-|', 'apt-get', 'indextargets', '--format', '$(FILENAME)', 'Created-By: Packages', "Architecture: $options->{nativearch}") or die "cannot start apt-get indextargets: $!";
+	open(my $pipe_apt, '-|', 'apt-get', 'indextargets', '--format', '$(FILENAME)', 'Created-By: Packages') or die "cannot start apt-get indextargets: $!";
 	while (my $fname = <$pipe_apt>) {
 	    chomp $fname;
 	    open (my $pipe_cat, '-|', '/usr/lib/apt/apt-helper', 'cat-file', $fname) or die "cannot start apt-helper cat-file: $!";
@@ -723,6 +723,7 @@ sub setup {
 	    my $pkgname;
 	    my $ess = '';
 	    my $prio = 'optional';
+	    my $arch = '';
 	    while (my $line = <$pipe_cat>) {
 		chomp $line;
 		# Dpkg::Index takes 10 seconds to parse a typical Packages
@@ -735,9 +736,14 @@ sub setup {
 			$ess = 'yes'
 		    } elsif ($line =~ /^Priority: (.*)/) {
 			$prio = $1;
+		    } elsif ($line =~ /^Architecture: (.*)/) {
+			$arch = $1;
 		    }
 		    next;
 		}
+		# we are only interested of packages of native architecture or
+		# Architecture:all
+		if ($arch eq $options->{nativearch} or $arch eq 'all') {
 		    # the line is empty, thus a package stanza just finished
 		    # processing and we can handle it now
 		    if ($ess eq 'yes') {
@@ -766,10 +772,12 @@ sub setup {
 		    } else {
 			die "unknown variant: $options->{variant}";
 		    }
+		}
 		# reset values
 		undef $pkgname;
 		$ess = '';
 		$prio = 'optional';
+		$arch = '';
 	    }
 
 	    close $pipe_cat;