rra-c-util is Russ Allbery's collection of portability functions, utility functions, Autoconf macros, and related shared C infrastructure, akin to gnulib but without any GPL-covered code and additional support for Kerberos and PAM development. It serves as a common repository of code and infrastructure used across multiple projects so that files have a canonical latest version. It's not intended for installation as a regular package; instead, other packages are expected to copy files from here as needed.