Snippets for libzip 1.11.4 from FreeBSD 151arm64

Sourced from https://pkg-status.freebsd.org/ampere5/data/latest-per-pkg/libzip/1.11.4/151arm64-default.log.

• /wrkdirs/usr/ports/archivers/libzip/work/.build/config.h:60:9: warning: 'HAVE_UNISTD_H' macro redefined [-Wmacro-redefined]
     60 | #define HAVE_UNISTD_H
        |         ^