Wanted to try out the latest 1.10.6 FreeSWITCH release so I updated its build expression (derivation?) and ran
nix-shell -I nixpkgs=~/clones/nixpkgs -p freeswitch`
The compilation process spit out a whole lot of warnings like the ones below, but it did compile successfully.
configure.ac:19: warning: The macro `AC_CONFIG_HEADER' is obsolete.
configure.ac:19: You should run autoupdate.
./lib/autoconf/status.m4:719: AC_CONFIG_HEADER is expanded from...
configure.ac:19: the top level
Nix/Os tends to be updated quicky, and uses quite new tools. This is warning, and the build code needs updating/refactoring to use newer Autotools standards.
*** AC_CONFIG_HEADER is now diagnosed as obsolete, and replaced with
AC_CONFIG_HEADERS by autoupdate.
This macro has been considered obsolete for many years and was not
documented at all.
but like all code, it remains,…for ever. This is an issue that needs to be fixed upstream at some point , if it still maintained.