include objc workaround for linux

Author: ktoso

Samples/JExtractPluginSampleApp/Sources/JExtractPluginSampleLib/MyCoolSwiftClass.swift

@@ -25,8 +25,11 @@ public class MyCoolSwiftClass {
   }
 }
 
+#if os(Linux)
+// FIXME: why do we need this workaround?
 @_silgen_name("_objc_autoreleaseReturnValue")
 public func _objc_autoreleaseReturnValue(a: Any) {}
 
 @_silgen_name("objc_autoreleaseReturnValue")
 public func objc_autoreleaseReturnValue(a: Any) {}
+#endif

Samples/SwiftKitSampleApp/Sources/MySwiftLibrary/MySwiftLibrary.swift

@@ -90,3 +90,12 @@ private func p(_ msg: String, file: String = #fileID, line: UInt = #line, functi
   print("[swift][\(file):\(line)](\(function)) \(msg)")
   fflush(stdout)
 }
+
+#if os(Linux)
+// FIXME: why do we need this workaround?
+@_silgen_name("_objc_autoreleaseReturnValue")
+public func _objc_autoreleaseReturnValue(a: Any) {}
+
+@_silgen_name("objc_autoreleaseReturnValue")
+public func objc_autoreleaseReturnValue(a: Any) {}
+#endif

Sources/ExampleSwiftLibrary/MySwiftLibrary.swift

@@ -101,3 +101,12 @@ private func p(_ msg: String, file: String = #fileID, line: UInt = #line, functi
   print("[swift][\(file):\(line)](\(function)) \(msg)")
   fflush(stdout)
 }
+
+#if os(Linux)
+// FIXME: why do we need this workaround?
+@_silgen_name("_objc_autoreleaseReturnValue")
+public func _objc_autoreleaseReturnValue(a: Any) {}
+
+@_silgen_name("objc_autoreleaseReturnValue")
+public func objc_autoreleaseReturnValue(a: Any) {}
+#endif