mount symlink dirs in snapshot as host volumes

Docker simply doesn't handle symlinks in host volumes properly. The
symlink target is essentially lost when host mounting the directory that
contains the symlink. So, this patch manually mounts all symlinks in the
ghw static snapshot as separate host mounts pointing to the original
target directory.

Nasty Bash and sed ensued.

Issue #758

hack/run-against-snapshot.sh

@@ -21,6 +21,16 @@ echo "building Docker image with ghwc ..."
 
 docker build -f $root_dir/Dockerfile -t $ghwc_image_name:$IMAGE_VERSION $root_dir
 
+echo "gathering symlink dirs in extracted snapshot to host volume mount ..."
+
+linkdirs=""
+for dirlink in `find -L $snap_tmp_dir -xtype l`; do
+    sourcelink=$( readlink $dirlink )
+    sourcelink=$( echo $sourcelink | sed "s/\/tmp\/ghw-snapshot[[:digit:]]\+/$tmp_snap_dir/")
+    target=$( echo "$dirlink" | sed "s/\/tmp\/ghw-snap-test-.../\/host/")
+    linkdirs+=" --mount type=bind,source=$sourcelink,destination=$target"
+done
+
 echo "running ghwc Docker image with volume mount to snapshot dir ..."
 
-docker run -it -v $snap_tmp_dir:/host -e GHW_CHROOT="/host" $ghwc_image_name:$IMAGE_VERSION 
+docker run -it -v $snap_tmp_dir:/host $linkdirs -e GHW_CHROOT="/host" $ghwc_image_name:$IMAGE_VERSION