There appears to be issue signature problem with the PPA package we use,
so workaround it this way for now. Warning: with broken signature, there's
always a possibility that PPA was hacked and ships trojaned binaries.

ussl was in testing mode for 8 months, and now enabled in other ports
(e.g. esp8266), so time for unix port to catch up.

Still not compatible with nanboxing.

Useful to check file/dir operations result, in particular used by upip.

So, keep call to it protected via NLR still.

So the documentation's example works.  Besides, a tuple can be more
memory efficient.

To use, put your directory structure with .py files in frozen/ and then:

    make FROZEN_MPY_DIR=frozen

When rendering the qstr for a C header file, the double-quate character
must be escaped.

See issue #1814.

Directories are now supported by the frozen import system (to implement
frozen packages) so we should keep them.

.mpy files contain the name of the source file that they were compiled
from.  This patch adds a way to change this name to an arbitrary string,
specified on the command line with the -s option.  The default is to use
the full name of the input filename.

This new -s option is useful to strip off a leading directory name so
that mpy-tool.py can freeze packages.

So that it can be correctly stat'd when looking for frozen files.

Freezing mpy files using mpy-tool.py now works again.

In particular, disclose the fact that server certificates are not
validated.

Disabled by default, enabled in unix port. Need for this method easily
pops up when working with text UI/reporting, and coding workalike
manually again and again counter-productive.

These are workarounds required until frozen .mpy loading following standard
frozen modules code path.

Frozen modules are now stored with extensions and with '/' as path
separator. In other words, frozen modules paths stored as they are
in normal filesystem.

Now frozen modules is treated just as a kind of VFS, and all operations
performed on it correspond to operations on normal filesystem. This allows
to support packages properly, and potentially also data files.

This change also have changes to rework frozen bytecode modules support to
use the same framework, but it's not finished (and actually may not work,
as older adhox handling of any type of frozen modules is removed).

Similar to existing mp_hal_ticks_ms().

Similar to existing mp_hal_delay_ms/mp_hal_ticks_ms.

Make dupterm subsystem close a term stream object when EOF or error occurs.
There's no other party than dupterm itself in a better position to do this,
and this is required to properly reclaim stream resources, especially if
multiple dupterm sessions may be established (e.g. as networking
connections).

Otherwise some compilers (eg without optimisation) will put this read-only
data in RAM instead of ROM.

APA102 is a new "smart LED", similar to WS2812 aka "Neopixel".