Fix some samples after adding platform libs:

* objc
* uikit

samples/objc/build.gradle

@@ -1,14 +1,7 @@
 apply plugin: 'konan'
 
-konanInterop {
-    objective_c {
-        target "macbook"
-    }
-}
-
 konanArtifacts {
     Window {
-        useInterop 'objective_c'
         target "macbook"
     }
 }

samples/objc/src/main/c_interop/objective_c.def

@@ -1,4 +0,0 @@
-headers = Foundation/Foundation.h Cocoa/Cocoa.h AppKit/NSApplication.h AppKit/NSWindow.h
-headerFilter = Foundation/** Cocoa/** AppKit/**
-language = Objective-C
-linkerOpts = -framework AppKit

samples/objc/src/main/kotlin/Window.kt

@@ -1,7 +1,8 @@
+import kotlinx.cinterop.*
+import platform.AppKit.*
+import platform.Foundation.*
 import platform.objc.*
 import platform.osx.*
-import objective_c.*
-import kotlinx.cinterop.*
 
 fun main(args: Array<String>) {
     autoreleasepool {

samples/uikit/build.gradle

@@ -1,15 +1,7 @@
 apply plugin: 'konan'
 
-konanInterop {
-    objc {
-        target "iphone"
-    }
-}
-
-
 konanArtifacts {
     app {
-        useInterop 'objc'
         target "iphone"
     }
 }

samples/uikit/src/main/c_interop/objc.def

@@ -1,4 +0,0 @@
-headers = Foundation/Foundation.h UIKit/UIKit.h
-headerFilter = Foundation/** UIKit/**
-language = Objective-C
-linkerOpts = -framework Foundation -framework UIKit

samples/uikit/src/main/kotlin/main.kt

@@ -1,5 +1,6 @@
-import objc.*
 import kotlinx.cinterop.*
+import platform.Foundation.*
+import platform.UIKit.*
 
 fun main(args: Array<String>) {
     memScoped {