我正在尝试使用英特尔的mpicc，并且已经设置

  export I_MPI_CC=icc

，但尚未正确配置mpicc。调用mpicc时，我仍然得到：

    $mpicc
      This script invokes an appropriate specialized C MPI compiler driver.
      The following ways (priority order) can be used for changing default
      compiler name (gcc):
           1. Command line option:  -cc=<compiler_name>
           2. Environment variable: I_MPI_CC (current value 'icc')
           3. Environment variable: MPICH_CC (current value '')

很明显，我正在使用option2。我在做什么错了？