Samples: Drop MPPTools + migrate to KTS

samples/workers/build.gradle

@@ -1,16 +0,0 @@
-plugins {
-    id 'kotlin-multiplatform'
-}
-
-// Determine host preset.
-def hostPreset = MPPTools.defaultHostPreset(project)
-
-kotlin {
-    targetFromPreset(hostPreset, 'workers') {
-        binaries {
-            executable() {
-                entryPoint = 'sample.workers.main'
-            }
-        }
-    }
-}

samples/workers/build.gradle.kts

@@ -0,0 +1,27 @@
+import org.jetbrains.kotlin.gradle.plugin.mpp.KotlinNativeTargetPreset
+
+plugins {
+    kotlin("multiplatform")
+}
+
+// Determine host preset.
+val hostOs = System.getProperty("os.name")
+
+val hostPreset: KotlinNativeTargetPreset = when {
+    hostOs == "Mac OS X" -> "macosX64"
+    hostOs == "Linux" -> "linuxX64"
+    hostOs.startsWith("Windows") -> "mingwX64"
+    else -> throw GradleException("Host OS '$hostOs' is not supported in Kotlin/Native $project.")
+}.let {
+    kotlin.presets[it] as KotlinNativeTargetPreset
+}
+
+kotlin {
+    targetFromPreset(hostPreset, "workers") {
+        binaries {
+            executable {
+                entryPoint = "sample.workers.main"
+            }
+        }
+    }
+}