message: Add support for custom environments settings
  support environment, buildEnvironment
diff: @@ -222,6 +222,7 @@ export abstract class CMakeDriver implements vscode.Disposable {
  const cur_env = process.env as proc.EnvironmentVariables;
  const env = util.mergeEnvironment(cur_env,
  this.getKitEnvironmentVariablesObject(),
  + config.environment,
  (options && options.environment) ? options.environment : {});
  const exec_options = Object.assign({}, options, {environment : env});
  return proc.execute(command, args, consumer, exec_options);
  @@ -644,7 +645,7 @@ export abstract class CMakeDriver implements vscode.Disposable {
  const args = [ '--build', this.binaryDir, '--config', this.currentBuildType, '--target', target, '--' ].concat(
  generator_args);
  const cmake = await paths.cmakePath;
  - const child = this.executeCommand(cmake, args, consumer);
  + const child = this.executeCommand(cmake, args, consumer, {environment : config.buildEnvironment});
  this._currentProcess = child;
  await child.result;
  this._currentProcess = null;
  