Fixes

checking for ranlib... /nix/store/p3kn26g5nhmx6spn37ar3mn0xjbzks3g-binutils-2.31.1/bin/ranlib
checking for rpcgen... no
configure: error: required program RPCGEN not found

and

In file included from ../include/automount.h:33,
                 from cache.c:25:
../include/rpc_subs.h:19:10: fatal error: rpc/rpc.h: No such file or directory
   19 | #include <rpc/rpc.h>
      |          ^~~~~~~~~~~
compilation terminated.

Merge after #104774

Motivation for this change

#104774 (comment)

Things done

• Tested using sandboxing (nix.useSandbox on NixOS, or option sandbox in nix.conf on non-NixOS linux)
• Built on platform(s)
  • NixOS
  • macOS
  • other Linux distributions
• Tested via one or more NixOS test(s) if existing and applicable for the change (look inside nixos/tests)
• Tested compilation of all pkgs that depend on this change using nix-shell -p nixpkgs-review --run "nixpkgs-review wip"
• Tested execution of all binary files (usually in ./result/bin/)
• Determined the impact on package closure size (by running nix path-info -S before and after)
• Ensured that relevant documentation is up to date
• Fits CONTRIBUTING.md.