message: show error message on tmpdir
diff: @@ -25,7 +25,12 @@ export class Builder {
  constructor(extension: Extension) {
  this.extension = extension
  + try {
  this.tmpDir = tmp.dirSync({unsafeCleanup: true}).name.split(path.sep).join('/')
  + } catch (e) {
  + vscode.window.showErrorMessage('Error during making tmpdir to build TeX files. Please check the environment variables, TEMP, TMP, and TMPDIR on your system.')
  + throw e
  + }
  this.buildMutex = new Mutex()
  this.waitingForBuildToFinishMutex = new Mutex()
  try {
  