Bump bundled libarchive version to 3.5.2

- Update bunlded libarchive version used on Windows/Mac
- Enable requested zstd support while we are at it. Closes #211

dependencies/zstd-1.5.0/contrib/linux-kernel/squashfs-benchmark.sh

@@ -0,0 +1,39 @@
+# !/bin/sh
+set -e
+
+# Benchmarks run on a Ubuntu 14.04 VM with 2 cores and 4 GiB of RAM.
+# The VM is running on a Macbook Pro with a 3.1 GHz Intel Core i7 processor and
+# 16 GB of RAM and an SSD.
+
+# $BENCHMARK_DIR is generated with the following commands, from the Ubuntu image
+# ubuntu-16.10-desktop-amd64.iso.
+# > mkdir mnt
+# > sudo mount -o loop ubuntu-16.10-desktop-amd64.iso mnt
+# > cp mnt/casper/filesystem.squashfs .
+# > sudo unsquashfs filesystem.squashfs
+
+# $HOME is on a ext4 filesystem
+BENCHMARK_DIR="$HOME/squashfs-root/"
+BENCHMARK_FS="$HOME/filesystem.squashfs"
+
+# Normalize the environment
+sudo rm -f $BENCHMARK_FS 2> /dev/null > /dev/null || true
+sudo umount /mnt/squashfs 2> /dev/null > /dev/null || true
+
+# Run the benchmark
+echo "Compression"
+echo "sudo mksquashfs $BENCHMARK_DIR $BENCHMARK_FS $@"
+time sudo mksquashfs $BENCHMARK_DIR $BENCHMARK_FS $@ 2> /dev/null > /dev/null
+
+echo "Approximate compression ratio"
+printf "%d / %d\n"                                                             \
+  $(sudo du -sx --block-size=1 $BENCHMARK_DIR | cut -f1)                       \
+  $(sudo du -sx --block-size=1 $BENCHMARK_FS  | cut -f1);
+
+# Mount the filesystem
+sudo mount -t squashfs $BENCHMARK_FS /mnt/squashfs
+
+echo "Decompression"
+time sudo tar -c /mnt/squashfs 2> /dev/null | wc -c > /dev/null
+
+sudo umount /mnt/squashfs