prod/doc/figfilt: script to filter portions of a FIG file based on keys in comments

This file is part of the production documentation build process but was
never committed.

prod/doc/figfilt

@@ -0,0 +1,18 @@
+#!/usr/bin/perl
+$key = shift @ARGV;
+$skip = 0;
+$skipping = 0;
+while (<>) {
+	if (/^#/ && $. != 1) {
+		$skip = $_ !~ /$key/;
+		print unless $skip;
+		next;
+	}
+	if (/^\s/) {
+		print unless $skipping;
+		next;
+	}
+	print unless $skip;
+	$skipping = $skip;
+	$skip = 0;
+}