Add extra logic to source-tracking code. If we have more than 1 binary

arch along with source, there's a chance that the different arches may
have refs to a particular binary package (and hence its source) at
completely different points. Rather than just go with the one we find
first (from the first binary ref), make sure that the source will
match up with the earliest binary record, measured across all arches.

As noticed on the multi-arch DVD; make sure that source:kde-i18n makes
it into the package list before amd64:kde-i18n-ar.

tools/merge_package_lists

@@ -90,16 +90,34 @@ if [ $source = "yes" ] ; then
 				    split($0,fields,":")
 					arch=fields[1]
 					pkg=fields[2]
-					if (!included[bin2src[pkg]]) {
-					  print "# Adding source " bin2src[pkg] " because of " pkg
-					  included[bin2src[pkg]] = pkg
-					  printf("%d:aaaaaaaaaaaaaaaaaa:%s\n", FNR, pkg)
+					source=bin2src[pkg]
+					if (!included[source]) {
+					  printf("# Adding source %s at %d because of %s:%s\n",
+					      source, FNR, arch, pkg)
+					  included[source] = pkg
+					  incarch[source] = arch
+					  indexnr[source] = FNR
 					} else {
-					  print "# Not adding pkg " pkg " source (" bin2src[pkg] "), already added due to " included[bin2src[pkg]]
+					  if (FNR < indexnr[source]) {
+					    printf("# Updating source %s: was due to %d:%s:%s, now moved earlier because of %d:%s:%s\n",
+						source, indexnr[source],
+						incarch[source], included[source],
+						FNR, arch, pkg);
+					    included[source] = pkg
+					    incarch[source] = arch
+					    indexnr[source] = FNR
+					  } else {
+					    printf("# Not adding pkg %s source (%d:%s:%s), already added due to %d:%s:%s\n", pkg, FNR, arch, source, indexnr[source], incarch[source], included[source])
+					    }
 					}
 					printf("%d:%s\n", FNR, $0)
 				  }
-				} ' $ADIR/$CODENAME-source/apt-state/lists/*Sources $BDIR/DONE $list | sort -nk 1 -t : >> $BDIR/list.mid
+				}
+	END {
+	    for (source in included) {
+		printf("%d:aaaaaaaaaaaaaaaaaa:%s\n", indexnr[source], source)
+	    }
+	}' $ADIR/$CODENAME-source/apt-state/lists/*Sources $BDIR/DONE $list | sort -nk 1 -t : >> $BDIR/list.mid
 else
 	awk '{printf("%d:%s\n", FNR, $0)}' $list | sort -nk 1 -t : >> $BDIR/list.mid
 fi