darwin: fix *_cmds installation

These just copy commands from Products/Release/. But with #52256 we
now build .dsym directories that somehow wind up in Products/Release/.
This makes things more exact by just copying the files in Products/Release/.

pkgs/os-specific/darwin/apple-source-releases/developer_cmds/default.nix

@@ -10,8 +10,11 @@ appleDerivation rec {
 
   # temporary install phase until xcodebuild has "install" support
   installPhase = ''
-    mkdir -p $out/bin/
-    install Products/Release/* $out/bin/
+    for f in Products/Release/*; do
+      if [ -f $f ]; then
+        install -D $f $out/bin/$(basename $f)
+      fi
+    done
 
     for n in 1; do
       mkdir -p $out/share/man/man$n