mpd: fix build on darwin

[kero0]

Things done

mpd is failing to build on darwin with this error

/nix/store/245wgmjlkq2swfkb138xh1jvb41ag8mh-libcxx-19.1.2+apple-sdk-15.5/include/c++/v1/__format/formatter_floating_point.h:67:30: error: 'to_chars' is unavailable: introduced in macOS 13.3
   67 |   to_chars_result __r = std::to_chars(__first, __last, __value, __fmt);
      |                              ^

This PR fixes the build error by adding "-mmacosx-version-min=13.3" to CXX_FLAGS.

• Built on platform:
  • x86_64-linux
  • aarch64-linux
  • x86_64-darwin
  • aarch64-darwin
• Tested, as applicable:
  • NixOS tests in nixos/tests.
  • Package tests at passthru.tests.
  • Tests in lib/tests or pkgs/test for functions and "core" functionality.
• Ran nixpkgs-review on this PR. See nixpkgs-review usage.
• Tested basic functionality of all binary files, usually in ./result/bin/.
• Nixpkgs Release Notes
  • Package update: when the change is major or breaking.
• NixOS Release Notes
  • Module addition: when adding a new NixOS module.
  • Module update: when the change is significant.
• Fits CONTRIBUTING.md, pkgs/README.md, maintainers/README.md and other READMEs.

---

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[kero0]

This is my first PR here. Please tell me if there's anything I need to change to get this merged 😄

[siraben]

nixpkgs-review result

Generated using nixpkgs-review.

Command: nixpkgs-review pr 457144
Commit: ae8a6a5efda5343e2da14de0d25246c770ac8852

---

aarch64-darwin

✅ 5 packages built:

• mpd
• mpd-small
• mpd-small.doc
• mpd.doc
• mpd.man

[tobim]

Thanks for this fix. I'm slightly unhappy about the consequence that many older devices won't be able to run mpd any more, but that is precisely something that many people repurpose them for.

Can you check if this alternative workaround also fixes the build:

diff --git i/pkgs/by-name/mp/mpd/package.nix w/pkgs/by-name/mp/mpd/package.nix
index 3bcc8851ae0a..14f600a77a12 100644
--- i/pkgs/by-name/mp/mpd/package.nix
+++ w/pkgs/by-name/mp/mpd/package.nix
@@ -234,7 +234,13 @@ stdenv.mkDerivation (finalAttrs: {
         substituteInPlace src/output/plugins/OSXOutputPlugin.cxx \
           --replace kAudioObjectPropertyElement{Main,Master} \
           --replace kAudioHardwareServiceDeviceProperty_Virtual{Main,Master}Volume
-      '';
+      ''
+    +
+      lib.optionalString
+        (stdenv.hostPlatform.isDarwin && lib.versionOlder stdenv.hostPlatform.darwinSdkVersion "13.3")
+        ''
+          sed -i "/subdir('time')/d" test/meson.build
+        '';

   # Otherwise, the meson log says:
   #

In case it won't I will approve your change to set the deployment target.

[Rhys-T]

Ran into this same error on a couple of my out-of-tree packages. I managed to track it down to the libc++ change in #398727: The Apple libc++ implements std::format on top of to_chars, which only exists in the newer versions of macOS.

In this case, mpd itself is using fmt rather than the native std::format, so it shouldn't be running into this… but that one test subdirectory is using gtest, which is using std::format.

[kero0]

@tobim I checked your patch and it also worked. I've updated the branch.

[tobim]

@tobim I checked your patch and it also worked. I've updated the branch.

Great, thanks! Please you drop the original commit instead of adding a revert and change the title of the final commit to something like:

mpd: fix build on darwin

[kero0]

Ok. Done 😄

[tobim]

Thanks!

[nixos-discourse]

This pull request has been mentioned on NixOS Discourse. There might be relevant details there:

https://discourse.nixos.org/t/prs-already-reviewed/2617/2625