Improved exception handling in gen-config.

src/gen-config.cr

@@ -197,5 +197,10 @@ rescue e : GenConfig::Exception
 rescue e : Crinja::TypeError
 	STDERR.puts "Error reading template: #{e.message}"
 	exit 1
+rescue e
+	STDERR.puts "unhandled exception: #{e.message}"
+	e.backtrace.map do |line|
+		STDERR << "  - " << line << '\n'
+	end
 end