This happened when the overflow counter for ticks_ms() was interrupted
by an external hard interrupt (issue #3076).

There're a lot of changes and fixes in 1.8 regarding IP stack,
incompatible with previous Zephyr versions, so supporting them
doesn't make sense.

This is  the last commit which should build with Zephyr 1.7.

For x86_64 build, this saves only 128 bytes on the final executable
size, but still an improvement.

Make esp8266_common.ld export size reserved to all code segments, and use
that in esp.flash_user_start() implementation.

To accommodate both system and user frozen modules.

Tests for an issue with line continuation failing in paste mode due to the
lexer only checking for \n in the "following" character position, before
next_char() has had a chance to convert \r and \r\n to \n.

Resolves an issue where lexer failed to accept CR after line continuation
character.  It also simplifies the code.

This is a temporary hack to allow othe Makefiles to build mpy-cross
recursively.

This ensures that mpy-cross is automatically built (and is up-to-date) for
ports that use frozen bytecode.  It also makes sure that .mpy files are
re-built if mpy-cross is changed.

VfsFat no longer has the listdir() method.  Rather, if listdir()
functionality is needed then one should use uos.listdir() which will call
VfsFat.ilistdir().

uos.ilistdir() is the core function, returning an iterator that yields
3-tuples.  uos.listdir() is implemented in terms of ilistdir().

Otherwise the existing FSs can interfere with the tests, and in some
cases the tests can write to the real FS on the device.

Now consistently uses the EOL processing ("\r" and "\r\n" convert to "\n")
and EOF processing (ensure "\n" before EOF) provided by next_char().

In particular the lexer can now correctly handle input that starts with CR.

Prior to this patch only 'q' and 'Q' type arrays could store big-int
values.  With this patch any big int that is stored to an array is handled
by the big-int implementation, regardless of the typecode of the array.
This allows arrays to work with all type sizes on all architectures.

This will lead to crash like:

FATAL: uncaught NLR 80a5420

On x86_32, the minimum heap size is smaller, but not 2 times, so just
use value which works for x86_64.

It's now possible to use the name "super" as a local variable.

This patch ensures that int.from_bytes only creates a big-int if necessary,
by checking the value for a small-int overflow as it's being parsed.

Don't print dupe ">>> " prompt when starting event-driven REPL.  Clear
incomplete line in transition from raw to friendly REPL.