added build instructions

BUILD.md

@@ -0,0 +1,49 @@
+# Build Instructions
+
+## Install Chocolatey <https://chocolatey.org/install>
+
+- put this in an elevated "admin" powershell
+
+```powershell
+Set-ExecutionPolicy Bypass -Scope Process -Force; [System.Net.ServicePointManager]::SecurityProtocol = [System.Net.ServicePointManager]::SecurityProtocol -bor 3072; iex ((New-Object System.Net.WebClient).DownloadString('https://community.chocolatey.org/install.ps1'))
+```
+
+- close the powershell
+- open an elevated "admin" powershell or cmd
+
+```powershell
+choco install go
+choco install mingw
+```
+
+## Test go / gcc
+
+- close the powershell
+- open a non elevated powershell or cmd
+
+```cmd
+C:\>go version
+go version go1.22.2 windows/amd64
+
+C:\>gcc --version
+gcc (x86_64-posix-seh-rev0, Built by MinGW-Builds project) 13.2.0
+Copyright (C) 2023 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.
+```
+
+## Build
+
+- open a non elevated powershell or cmd
+
+GUI version
+
+```cmd
+build.bat
+```
+
+CLI version
+
+```cmd
+build_cli.bat
+```