SA_SIGINFO allows the signal handler to access more information about
the signal, especially useful in a threaded environment. The extra
information is not currently used but it may prove useful in the future.
GC_EXIT() can cause a pending thread (waiting on the mutex) to be
scheduled right away. This other thread may trigger a garbage
collection. If the pointer to the newly-allocated block (allocated by
the original thread) is not computed before the switch (so it's just left
as a block number) then the block will be wrongly reclaimed.
This patch makes sure the pointer is computed before allowing any thread
switch to occur.
By using a single, global mutex, all memory-related functions (alloc,
free, realloc, collect, etc) are made thread safe. This means that only
one thread can be in such a function at any one time.
The linker flag --gc-sections is not available on the linker used on
Mac OS X which results in an error when linking micropython on Mac OS X.
Therefore move this option to the LDFLAGS_ARCH variable on non Darwin
systems. According to http://stackoverflow.com/a/17710056 the equivalent
to --gc-sections is -dead_strip thus this option is used for the
LDFLAGS_ARCH on Darwin systems.
In particular, the WeMOS D1 Mini board comes with a shield that has a
64x48 OLED display. This patch makes it display properly, with the upper
left pixel being at (0, 0) and not (32, 0).
I tried to do this with the configuration commands, but there doesn't
seem to be a command that would set the column offset (there is one for
the line offset, though).