Issue in compiling this open source application

I am trying to set up and run LibreCAD and I am following their Build From Source Guide.

At some point, and after installing QT and boost, I reach the step where it says this:

To change these default settings you have to create the file scripts/custom-windows.bat and overwrite the different settings without effect to the SCM (git). Example for scripts/custom-windows.bat:
   set Qt_DIR=C:\Qt\5.4
   set NSIS_DIR=C:\PROGRA~2\NSIS
   set MINGW_VER=mingw491_32

So I created a custom-windows.bat file and overwrote the settings. Now, and since I am working on 64 bit Windows, They are saying that I need to do this:

There are issues with the NSIS_DIR path on 64 Bit Windows. When NSIS is installed in the Program Files (x86) folder and NSIS_DIR is added to the PATH, something goes wrong in the build process.

In this case use the command dir /X \ and get an output like this:
   09/02/2014  09:50 PM    <DIR>          PROGRA~1     Program Files
   10/27/2014  12:33 PM    <DIR>          PROGRA~2     Program Files (x86)
   08/16/2014  10:49 PM    <DIR>          Qt

But what does that mean? "..use the command dir /X \ and get the output.." Where and how? Appreciate it if anyone could tell me how to solve that.

Solution

Open up a command prompt and literally type dir /X \. The output will show the mapping between the short folder names and the long ones.

Your goal is to use the correct short form representation for Program Files (x86) in NSIS_DIR, since it's not always PROGRA~2. It can vary from filesystem to filesystem, based on the history of the filesystem.