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>