less: Do not trust st_size if it equals zero

[ricardobranco777]

Fix for less(1) not being to operate on files residing in pseudo-filesystems that advertize a zero size value.

Bug: https://bugs.freebsd.org/bugzilla/show_bug.cgi?id=276133

[igalic]

We usually want contrib to be merged upstream first.

[ricardobranco777]

We usually want contrib to be merged upstream first.

Fix merged upstream: gwsw/less#468

[igalic]

Thank you for tracking this, @ricardobranco777

as soon as they make a new release, we'll import it into our vendor/less branch: https://cgit.freebsd.org/src/log/?h=vendor/less

[emaste]

CC @delphij

[bsdimp]

Specifically, should we import, or just cherry-pick the patch...

[bsdimp]

This isn't in v643, but is in v653 (gwsw/less@1fafd96 shows it there), but isn't in the release notes. v653 is in beta testing right now, so once it's official, @delphij will important it and we'll close this... Reading the tea leaves suggests this will be soon enough that cherry-picking the change isn't needed, but I'll reevaluate next time I do a deep scrub of the PRs (just before BSDcan most likely).

[delphij]

Thanks for the PR. I'll commit this to vendor branch and merge this one. git will be able to handle it properly for future imports.

[delphij]

Merged as cae3362