Issue #3275324 by phenaproxima: If the PHP binary is not in the PHP...

    if ($this->isComposerCommand($command)) {

      $env['COMPOSER_HOME'] = $this->getComposerHomePath();

    }

    // Ensure that the running PHP binary is in the PATH.

    $env['PATH'] = $this->getEnv('PATH') . ':' . dirname(PHP_BINARY);

    // Ensure that the PHP interpreter is in the PATH.

    $env['PATH'] = $this->getEnv('PATH') . ':' . static::getPhpDirectory();

    return $process->setEnv($env);

  }

  /**

   * Returns the directory which contains the PHP interpreter.

   *

   * @return string

   *   The path of the directory containing the PHP interpreter. If the server

   *   is running in a command-line interface, the directory portion of

   *   PHP_BINARY is returned; otherwise, the compile-time PHP_BINDIR is.

   *

   * @see php_sapi_name()

   * @see https://www.php.net/manual/en/reserved.constants.php

   */

  protected static function getPhpDirectory(): string {

    if (PHP_SAPI === 'cli' || PHP_SAPI === 'cli-server') {

      return dirname(PHP_BINARY);

    }

    return PHP_BINDIR;

  }

  /**

   * Returns the path to use as the COMPOSER_HOME environment variable.

   *