odin: Fix arm64-apple-darwin builds (#429353)

pkgs/by-name/od/odin/package.nix

···
     # which can be provided by a pure Nix expression, for example in a shell.
     ./system-raylib.patch
   ];
+
   postPatch = ''
+    # Odin is still using 'arm64-apple-macos' as the target name on
+    # aarch64-darwin architectures. This results in a warning whenever the
+    # Odin compiler runs a build. Replacing the target in the Odin compiler
+    # removes the nix warning when the Odin compiler is ran on aarch64-darwin.
+    substituteInPlace src/build_settings.cpp \
+      --replace-fail "arm64-apple-macosx" "arm64-apple-darwin"
+
     rm -r vendor/raylib/{linux,macos,macos-arm64,wasm,windows}
 
     patchShebangs --build build_odin.sh