gupnp, gupnp_1_6: fix compilation

[uninsane]

meson 1.1.1 -> 1.2.0 had a few breaking changes. upstream fixed it on both the main 1.6 and legacy 1.4 branches, but only published a release for gupnp_1_6: for the legacy gupnp we have to cherry-pick that fix.

Description of changes

Things done

• Built on platform(s)
  • x86_64-linux
  • aarch64-linux
  • x86_64-darwin
  • aarch64-darwin
• For non-Linux: Is sandbox = true set in nix.conf? (See Nix manual)
• Tested, as applicable:
  • NixOS test(s) (look inside nixos/tests)
  • and/or package tests
  • or, for functions and "core" functionality, tests in lib/tests or pkgs/test
  • made sure NixOS tests are linked to the relevant packages
• Tested compilation of all packages that depend on this change using nix-shell -p nixpkgs-review --run "nixpkgs-review rev HEAD". Note: all changes have to be committed, also see nixpkgs-review usage
• Tested basic functionality of all binary files (usually in ./result/bin/)
• 23.11 Release Notes (or backporting 23.05 Release notes)
  • (Package updates) Added a release notes entry if the change is major or breaking
  • (Module updates) Added a release notes entry if the change is significant
  • (Module addition) Added a release notes entry if adding a new NixOS module
• Fits CONTRIBUTING.md.

[uninsane]

upstream was quick to backport the fix ❤️, so i updated the PR to fetchpatch it instead of including the patch inline.

i somehow didn't notice that gupnp_1_6 was also broken. i can push a commit to this PR to update to 1.6.5 in a bit here. pushed a commit to fix that: it's a dead simple upgrade.