feat: adds environment variable to allow PowerShell executable to be specified

Author: brianpursley

lib/find-visualstudio.js

@@ -127,6 +127,10 @@ VisualStudioFinder.prototype = {
   findVisualStudio2017OrNewer: function findVisualStudio2017OrNewer (cb) {
     var ps = path.join(process.env.SystemRoot, 'System32',
       'WindowsPowerShell', 'v1.0', 'powershell.exe')
+    if (process.env.NODE_GYP_POWERSHELL_PATH) {
+      ps = path.resolve(process.env.NODE_GYP_POWERSHELL_PATH)
+      this.addLog('PowerShell path has been set by NODE_GYP_POWERSHELL_PATH:', ps)
+    }
     var csFile = path.join(__dirname, 'Find-VisualStudio.cs')
     var psArgs = [
       '-ExecutionPolicy',