run chmod -R a+rX $(STORE) before creating sqfs

[simonpintarelli]

Should we run chmod -R a+rX $(STORE) before creating the squashfs file?

Currently chmod needs to be run manually in post-install. User wouldn't need to think about this when writing post-install hooks.

Ping @lukasgd.

[bcumming]

Naive question: what is the reason for this?

[simonpintarelli]

For example when manually installing packages in post-install, it is likely one needs to add chmod, since the files are owned by root and not world-readable:
https://github.com/biddisco/alps-spack-stacks/blob/paraview/recipes/paraview/5.13.2/gh200/post-install#L208

Having everything in $(STORE) world-readable seems a sane default. Although currently it is mostly redundant, since we take care of permissions for the bulk of the files in other places.