Fix Linux posix_spawn compatibility

Sources/CodexBarCore/Host/Process/PosixSpawnFileActionsCloseFrom.swift

@@ -44,7 +44,7 @@ enum PosixSpawnFileActionsCloseFrom {
         startingAt minimumFileDescriptor: Int32) throws
     {
         #if canImport(Glibc)
-        try self.check(posix_spawn_file_actions_addclosefrom_np(&fileActions, minimumFileDescriptor))
+        try self.check(PosixSpawnFileActionsCompatibility.addCloseFrom(&fileActions, startingAt: minimumFileDescriptor))
         #else
         for descriptor in try self.descriptorsToClose(startingAt: minimumFileDescriptor) {
             try self.check(posix_spawn_file_actions_addclose(&fileActions, descriptor))

Sources/CodexBarCore/Host/Process/PosixSpawnFileActionsCompatibility.swift

@@ -0,0 +1,47 @@
+#if canImport(Darwin)
+import Darwin
+#elseif canImport(Glibc)
+import Glibc
+#elseif canImport(Musl)
+import Musl
+#endif
+
+#if canImport(Darwin)
+typealias PosixSpawnFileActionsHandle = posix_spawn_file_actions_t?
+#else
+typealias PosixSpawnFileActionsHandle = posix_spawn_file_actions_t
+#endif
+
+#if canImport(Glibc)
+@_silgen_name("posix_spawn_file_actions_addchdir_np")
+private func glibc_posix_spawn_file_actions_addchdir_np(
+    _ actions: UnsafeMutablePointer<posix_spawn_file_actions_t>,
+    _ path: UnsafePointer<CChar>) -> Int32
+
+@_silgen_name("posix_spawn_file_actions_addclosefrom_np")
+private func glibc_posix_spawn_file_actions_addclosefrom_np(
+    _ actions: UnsafeMutablePointer<posix_spawn_file_actions_t>,
+    _ fileDescriptor: Int32) -> Int32
+#endif
+
+enum PosixSpawnFileActionsCompatibility {
+    static func addChangeDirectory(
+        _ fileActions: inout PosixSpawnFileActionsHandle,
+        path: UnsafePointer<CChar>) -> Int32
+    {
+        #if canImport(Glibc)
+        glibc_posix_spawn_file_actions_addchdir_np(&fileActions, path)
+        #else
+        posix_spawn_file_actions_addchdir_np(&fileActions, path)
+        #endif
+    }
+
+    #if canImport(Glibc)
+    static func addCloseFrom(
+        _ fileActions: inout PosixSpawnFileActionsHandle,
+        startingAt minimumFileDescriptor: Int32) -> Int32
+    {
+        glibc_posix_spawn_file_actions_addclosefrom_np(&fileActions, minimumFileDescriptor)
+    }
+    #endif
+}

Sources/CodexBarCore/Host/Process/SpawnedProcessGroup.swift

@@ -469,7 +469,7 @@ package final class SpawnedProcessGroup: @unchecked Sendable {
         }
         if let workingDirectory {
             fileActionResults.append(workingDirectory.path.withCString { path in
-                posix_spawn_file_actions_addchdir_np(&fileActions, path)
+                PosixSpawnFileActionsCompatibility.addChangeDirectory(&fileActions, path: path)
             })
         }
         #if canImport(Glibc) || canImport(Musl)

Sources/CodexBarCore/Providers/Antigravity/AntigravityCLISession.swift

@@ -884,7 +884,7 @@ struct AntigravityPTYProcessLauncher: AntigravityCLIProcessLaunching {
 
         let homeDirectory = NSHomeDirectory()
         _ = homeDirectory.withCString { path in
-            posix_spawn_file_actions_addchdir_np(&fileActions, path)
+            PosixSpawnFileActionsCompatibility.addChangeDirectory(&fileActions, path: path)
         }
         #if canImport(Glibc) || canImport(Musl)
         do {