Sean Burton e33bc59712 py: Remove calls to file reader functions when these are disabled.
If MICROPY_PERSISTENT_CODE_LOAD or MICROPY_ENABLE_COMPILER are enabled then
code gets enabled that calls file reading functions which may be disabled
if no readers have been implemented.

To fix this, introduce a MICROPY_HAS_FILE_READER variable, which is
automatically set if MICROPY_READER_POSIX or MICROPY_READER_VFS is set but
can also be manually set if a custom reader is being implemented.  Then
disable the file reading calls if this is not set.
2019-01-27 11:08:25 +11:00
..
2017-07-18 11:57:39 +10:00
2018-12-04 01:03:44 +11:00
2017-07-18 11:57:39 +10:00