 - Only define mpi_read_file and mpi_write_file if POLARSSL_FS_IO is present
 - Only define mpi_read_file and mpi_write_file if POLARSSL_FS_IO is present


ARMmbed/mbedtls,Mbed-TLS/mbedtls,NXPmicro/mbedtls,Mbed-TLS/mbedtls,Mbed-TLS/mbedtls,NXPmicro/mbedtls,ARMmbed/mbedtls,ARMmbed/mbedtls,Mbed-TLS/mbedtls,NXPmicro/mbedtls,NXPmicro/mbedtls,ARMmbed/mbedtls