Add fallback search paths for Unix utilities

On macOS, some projects manipulate PATH and become unable to find chown due to the recent changes. To protect against this and similar future changes, add a set of default search paths for the typical Unix tool locations of /usr/{bin,sbin} and /{bin,sbin}, attempting to follow the usual relative orderings on each platform.

Author: jakepetroules

Sources/SWBCore/Settings/Settings.swift

@@ -1032,6 +1032,44 @@ extension WorkspaceContext {
                 }
             }
 
+            // Add the system-level bin directories common to most Unix-like platforms if they weren't already present.
+            // This is not an exhaustive list that exactly matches the platform defaults, but generally aims to follow the same relative ordering.
+            switch core.hostOperatingSystem {
+            case .macOS:
+                paths.append(contentsOf: [
+                    .root.join("usr").join("bin"),
+                    .root.join("bin"),
+                    .root.join("usr").join("sbin"),
+                    .root.join("sbin"),
+                ])
+            case .linux:
+                paths.append(contentsOf: [
+                    .root.join("usr").join("sbin"),
+                    .root.join("usr").join("bin"),
+                    .root.join("sbin"),
+                    .root.join("bin"),
+                ])
+            case .freebsd:
+                paths.append(contentsOf: [
+                    .root.join("sbin"),
+                    .root.join("bin"),
+                    .root.join("usr").join("sbin"),
+                    .root.join("usr").join("bin"),
+                ])
+            case .openbsd:
+                paths.append(contentsOf: [
+                    .root.join("bin"),
+                    .root.join("sbin"),
+                    .root.join("usr").join("bin"),
+                    .root.join("usr").join("sbin"),
+                ])
+            case .android:
+                // FIXME: where are system utilities on Android?
+                break
+            case .iOS, .tvOS, .watchOS, .visionOS, .windows, .unknown:
+                break
+            }
+
             return StackedSearchPath(paths: [Path](paths), fs: fs)
         }
     }