"accessing" comamnd-line AVR tools from an Arduino install...

With WINAVR becoming unmaintained, various people including myself are starting to think that the easiest way of getting a basic set of avr-gcc tools installed on your Windows system is to install Arduino, and use the tools that it includes.
But they're buried rather deeply, and a bit of a pain to get to.
So I wrote this batch script to go out and look at your Windows (XP, 7, 8, 10) system, find the Arduino tools (1.0.x, 1.6.5+, 1.8.x), and sticks them in the search path for that "Command Prompt" session. It gets avrdude too. It doesn't copy or actually install anything, so it's pretty quick. Now, command-line access to the bare compiler isn't a particularly wonderful development environment, but it might be good for a quick start...

C:\Users\User>e:install-avr-tools

No avr-gcc currently installed.
At least one Arduino install found.

Looks like C:\Program Files\Arduino1.8.0 has version
avr-gcc.exe (GCC) 4.9.2
Use C:\Program Files\Arduino1.8.0 ? [y/n]>y
Found avr-gcc
Checking tool versions

avr-gcc (GCC) 4.9.2
Copyright (C) 2014 Free Software Foundation, Inc.
This is free software; see the source for copying conditions.  There is NO
warranty; not even for MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.

avrdude: Version 6.3, compiled on Dec 16 2016 at 13:33:19
         Copyright (c) 2000-2005 Brian Dean, http://www.bdmicro.com/
         Copyright (c) 2007-2014 Joerg Wunsch
         System wide configuration file is "C:\Program Files\Arduino1.8.0\hardware\tools\avr\etc\avrdude.conf"

C:\Users\User>

Glad you got it working on 64-bit Windows! I noticed that issue when you first created the repository and made an attempt at fixing it but ended up giving up after banging my head against the stupidity of batch files for a while. Life would be so much more simple if things like parentheses, apostrophes, and spaces weren't allowed in paths.