Sorry, I had to look more into this XD so I deleted my previews comment. There was an Issue with _FORTIFY_SOURCE=2 for neovim for Arch since it is the default in the makepkg. From what I understand this is usually good so it should be kept the same for the makepkg, but it is not compatible with neovim so it is disabled in the Cmake file. I think the best way is to pass it as an argument flag to Cmake to silence the warning.
My first comment was wrong since it would force the _FORTIFY_SOURCE=2 so I edit it :), also thanks for maintaining this package.
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fwalch commented on 2016-07-04 19:52
Please don't flag this package out-of-date just because the version number displayed on AUR seems old. This is normal for VCS packages. As long as building the package works without problems, it isn't necessary to update the PKGBUILD here. makepkg will automatically retrieve the latest version when you build the package locally.