Properly alphabetize MAINTAINERS file

This adds a perl script to actually parse the MAINTAINERS file, clean up
some whitespace in it, warn about errors in it, and then properly sort
the end result.

My perl-fu is atrocious, so the script has basically been created by
randomly putting various characters in a pile, mixing them around, and
then looking it the end result does anything interesting when used as a
perl script.
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

scripts/parse-maintainers.pl

+#!/usr/bin/perl -w
+
+use strict;
+
+my %map;
+
+# sort comparison function
+sub by_category($$) {
+    my ($a, $b) = @_;
+
+    $a = uc $a;
+    $b = uc $b;
+
+    # This always sorts last
+    $a =~ s/THE REST/ZZZZZZ/g;
+    $b =~ s/THE REST/ZZZZZZ/g;
+
+    $a cmp $b;
+}
+
+sub alpha_output {
+    my $key;
+    my $sort_method = \&by_category;
+    my $sep = "";
+
+    foreach $key (sort $sort_method keys %map) {
+        if ($key ne " ") {
+            print $sep . $key . "\n";
+            $sep = "\n";
+        }
+        print $map{$key};
+    }
+}
+
+sub trim {
+    my $s = shift;
+    $s =~ s/\s+$//;
+    $s =~ s/^\s+//;
+    return $s;
+}
+
+sub file_input {
+    my $lastline = "";
+    my $case = " ";
+    $map{$case} = "";
+
+    while (<>) {
+        my $line = $_;
+
+        # Pattern line?
+        if ($line =~ m/^([A-Z]):\s*(.*)/) {
+            $line = $1 . ":\t" . trim($2) . "\n";
+            if ($lastline eq "") {
+                $map{$case} = $map{$case} . $line;
+                next;
+            }
+            $case = trim($lastline);
+            exists $map{$case} and die "Header '$case' already exists";
+            $map{$case} = $line;
+            $lastline = "";
+            next;
+        }
+
+        if ($case eq " ") {
+            $map{$case} = $map{$case} . $lastline;
+            $lastline = $line;
+            next;
+        }
+        trim($lastline) eq "" or die ("Odd non-pattern line '$lastline' for '$case'");
+        $lastline = $line;
+    }
+    $map{$case} = $map{$case} . $lastline;
+}
+
+&file_input;
+&alpha_output;
+exit(0);