Upstream backport.

Signed-off-by: Rosen Penev <rosenp@gmail.com>

All patches are not needed anymore. squashfs-tools has implemented them in
one way or another.

Converted to download release tarballs. This should work better to get
notified of a newer release.

Also adds support for ZSTD compression:
  https://facebook.github.io/zstd/

Signed-off-by: Alexandru Ardelean <ardeleanalex@gmail.com>

The inclusion of <sys/sysmacros.h> by <sys/types.h> was deprecated and
removed.  This is causing major, minor, and makedev to be undefined.

The patch is an upstream commit fixing it.

Signed-off-by: Eneas U de Queiroz <cotequeiroz@gmail.com>

squashfs-tools does not provide tar-balls.
It looks like a good time to pull a newer version
that obsoletes a few accepted patches.

Signed-off-by: Alexandru Ardelean <ardeleanalex@gmail.com>

Unsquashfs was segfaulting.  When examining in gdb the stack was corrupt.
I found that converting the variable length arrays to malloc caused the
stack corruption to not happen and the segfault went away.  This is due to
the musl pthread stack size being 80k by default.  So the chance of a stack
overflow is high.

Signed-off-by: Colby Whitney <colby.whitney@luxul.com>

Seems that this issue with squashfs-tools was fixed by the guys
at openembedded.
See patch here:
https://github.com/openembedded/openembedded-core/blob/master/meta/recipes-devtools/squashfs-tools/squashfs-tools/0001-mksquashfs.c-get-inline-functions-work-with-C99.patch

I think in my case, this issue appeared because I wrote the Makefile
some time ago and it worked, then when I did the PR for it,
it wasn't working anymore, and I assumed it was still working.

Signed-off-by: Alexandru Ardelean <ardeleanalex@gmail.com>

Picked up the old Makefile at 4.2.
Upgraded at 4.3 (repo move to github now: https://github.com/plougher/squashfs-tools/)
Added musl compatibility.
Enabled LZ4 compression support by default

Signed-off-by: Alexandru Ardelean <ardeleanalex@gmail.com>