You've only posted a few lines which doesn't include the actual error.
EDIT: Sorry, it does contain the error I just missed it
error: type of 'strlcpy' does not match original declaration [-Werror=lto-type-mismatch]
It's actually a warning, but the compiler was told to treat warnings as errors. In any case, it shouldn't occur it doesn't for me on Arch. Have you updated your installation? pacman -Syu
Another way to fix it would be to use strip_lto in the package.mk (see other packages for example) but like I said it shouldn't occur and I've confirmed it here by building open-vm-tools / libidnet with no issue.