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.

This patch allows mounting of VFS objects right at the root directory, eg
os.mount(vfs, '/').  It still allows VFS's to be mounted at a path within
the root, eg os.mount(vfs, '/flash'), and such mount points will override
any paths within a VFS that is mounted at the root.

Memory optimizations and error handling improvements.

Versions prior to v14.0 have a bug in parsing item functions when used
within a condition: https://github.com/Microsoft/msbuild/issues/368.
Since commit [db9c2e31] this results in an error when building MicroPython
with for example VS2013.
Fix this by creating an intermediate property.

fmode.c should only be included for builds targetting 'pure' windows, i.e.
msvc or mingw builds but not when using msys or cygwin's gcc (see #2298).
Just checking if the OS is windows and UNAME doesn't have msys stil leaves
the gate open for builds with cygwin's gcc since UNAME there is e.g.
CYGWIN_NT-6.1-WOW.
Fix this by checking for 'mingw' explicitly in the compiler version; both
gcc and clang have the -dumpmachine flag so the check should be ok for
all platforms.

The with semantics of this function is close to
pkg_resources.resource_stream() function from setuptools, which
is the canonical way to access non-source files belonging to a package
(resources), regardless of what medium the package uses (e.g. individual
source files vs zip archive). In the case of MicroPython, this function
allows to access resources which are frozen into the executable, besides
accessing resources in the file system.

This is initial stage of the implementation, which actually doesn't
implement "package" part of the semantics, just accesses frozen resources
from "root", or filesystem resource - from current dir.

Do not raise SIGPIPE, instead return EPIPE. Otherwise, e.g. writing
to peer-closed socket will lead to sudden termination of MicroPython
process. SIGPIPE is particularly nasty, because unix shell doesn't
print anything for it, so the above looks like completely sudden and
silent termination for unknown reason. Ignoring SIGPIPE is also what
CPython does. Note that this may lead to problems using MicroPython
scripts as pipe filters, but again, that's what CPython does. So,
scripts which want to follow unix shell pipe semantics (where SIGPIPE
means "pipe was requested to terminate, it's not an error"), should
catch EPIPE themselves.

Peer-closed socket is both readable and writable: read will return EOF,
write - error. Without this poll will hang on such socket.

Note that we don't return POLLHUP, based on argumentation in
http://www.greenend.org.uk/rjk/tech/poll.html that it should apply to
deeper disconnects, for example for networking, that would be link layer
disconnect (e.g. WiFi went down).

Add information as discussed in #2927 to the readme to make the easier
to discover.

By making sure we don't add relative paths to sys.path.

Make qstr generation depend on modifications in mpconfigport.h, mpconfig.h
and makeqstrdata.py and if any of those change scan all source files for
qstrs again since they might have changed (for example typcially when
enabling new features in mpconfig.h).
This fixes #2982 for msvc builds.

It is not used anywhere and causes a warning about redefinition because
it is used in modutimeq.c

The standard preprocessor definition to differentiate debug and non-debug
builds is NDEBUG, not DEBUG, so don't rely on the latter:
- just delete the use of it in objint_longlong.c as it has been stale code
  for years anyway (since commit [c4029e50]): SUFFIX isn't used anywhere.
- replace DEBUG with MICROPY_DEBUG_NLR in nlr.h: it is rarely used anymore
  so can be off by default

But warn if anything else but host/port is passed.

Similar to the implementation added to unix port module previously.

This follows previous refactor made to unix/moduselect.

extmod/crypto-algorithms/sha256.c was recently fixed so that it didn't
include this header.