rra-c-util 8.4

I've released a new version of my collection of utility libraries, Autoconf macros, and similar support infrastructure, primarily to include changes in the upcoming remctl and INN releases. Highlights:

• Add a new RRA_PROG_LD_FLAG Autoconf macro to check whether flags are supported by the linker, and add support for commas in flags passed to RRA_PROG_C_FLAG.

• NetBSD provides reallocarray but doesn't prototype it unless _OPENBSD_SOURCE is set. Autoconf 2.70 will set that flag when AC_USE_SYSTEM_EXTENSIONS is given, but it's not yet packaged for Debian. Work around this in the meantime by prototyping reallocarray if it's available but not prototyped. (NetBSD prefers reallocarr, which does indeed have a better API, but since no other operating system supports it, I'm sticking with reallocarray for now.)

• Fix the probe for AI_ADDRCONFIG on macOS.

• Fix the test suite for the portable getnameinfo replacement on musl libc, whose getaddrinfo returns the stringified version of an IP address if there is no reverse DNS. This seems like odd behavior and no other platform does this, but it's easy enough to work around.

The general support policy for rra-c-util is now that I will drop support for systems older than fifteen years if it becomes annoying to support them. That's still extremely conservative, but may let me drop some more support code that is essentially never used. The replacements for missing IPv6 functions are probably next on the chopping block.

Thanks to Julien ÉLIE and Bo Lindbergh for their contributions to this release.

You can get the latest release from the rra-c-util distribution page.