If any of the reserved members in lzma_stream are non-zero
or non-NULL, LZMA_OPTIONS_ERROR is returned. It is possible
that a new feature in the future is indicated by just setting
a reserved member to some other value, so the old liblzma
version need to catch it as an unsupported feature.

The non-standard ones from msvcrt.dll appear to work
most of the time with XZ Utils, but there are some
corner cases where things may go very wrong. So it's
good to use the better replacements provided by
MinGW(-w64) runtime.

This lets compiler use shifting instead of 64-bit division.

Adding support for LZMA_FINISH for Index encoding and
decoding needed tiny additions to the relevant .c files too.

lzma_chunk_size() was commented out because it is
currently useless.

This is similar to DOS/DJGPP that killing the program
with a signal will print a backtrace or a similar message.

SA_RESTART is not as portable as I had hoped. It's missing
at least from OpenVMS, QNX, and DJGPP). Luckily we can do
fine without SA_RESTART.

For some reason this prevented running the test only
on OS/2 and even on that it broke only recently.

Thanks to Elbert Pol.

Calling raise() to kill xz when user has pressed C-c
is a bit verbose on OS/2 and DOS/DJGPP. Instead of
calling raise(), set only the exit status to 1.

This is now simpler and builds only xz.exe.

This is simply for licensing reasons. The 64-bit version
will be built with MinGW-w64 anyway (at least for now),
so using it also for 32-bit build allows using the same
copyright notice about the MinGW-w64/w32 runtime.

Note that using MinGW would require a copyright notice too,
because its runtime is not in the public domain either even
though MinGW's home page claims that it is public domain.
See <http://marc.info/?l=mingw-users&m=126489506214078>.

Also, put README-Windows.txt to the doc directory like
the other documentation files.

630a8bed wasn't good.

Those are the same thing, and the former makes it a bit
easier to build the code with other build systems, because
one doesn't need to update the version number into custom
config.h.

This change affects only lzmainfo. Other tools were already
using LZMA_VERSION_STRING.

Most distros want xz linked against shared liblzma, so
it doesn't help much to require --enable-dynamic for that.
Those who want to avoid PIC on x86-32 to get better
performance, can still do it e.g. by using --disable-shared
to compile xz and then another pass to compile shared liblzma.

Part of these static/dynamic tricks were needed for Windows
in the past. Nowadays we rely on GCC and binutils to do the
right thing with auto-import. If the Autotooled build system
needs to support some other toolchain on Windows in the future,
this may need some rethinking.

Thanks to Jonathan Nieder.