tomlplusplus: disable broken tests on darwin (#352316)

pkgs/by-name/to/tomlplusplus/package.nix

@@ -44,12 +44,15 @@ stdenv.mkDerivation (finalAttrs: {
     glibcLocales
   ];
 
-  doCheck = true;
   mesonFlags = [
     "-Dbuild_tests=${lib.boolToString finalAttrs.doCheck}"
     "-Dbuild_examples=true"
   ];
 
+  # almost all tests fail on Darwin with the following exception:
+  # libc++abi: terminating due to uncaught exception of type std::runtime_error: collate_byname<char>::collate_byname failed to construct for
+  doCheck = !stdenv.hostPlatform.isDarwin;
+
   passthru = {
     updateScript = nix-update-script { };
     tests.pkg-config = testers.hasPkgConfigModules {