Build: Make task inputs relative to improve caching

core/builtins/build.gradle.kts

@@ -1,3 +1,4 @@
+import org.gradle.api.tasks.PathSensitivity.RELATIVE
 import java.io.File
 
 plugins {
@@ -20,9 +21,9 @@ val prepareSources by tasks.registering(Sync::class) {
 
 val serialize by tasks.registering(NoDebugJavaExec::class) {
     dependsOn(prepareSources)
-    val outDir = "$buildDir/$name"
+    val outDir = buildDir.resolve(name)
     val inDirs = arrayOf(builtinsSrc, builtinsNative, builtinsCherryPicked)
-    inDirs.forEach { inputs.dir(it) }
+    inDirs.forEach { inputs.dir(it).withPathSensitivity(RELATIVE) }
 
     outputs.dir(outDir)
     outputs.cacheIf { true }
@@ -30,7 +31,10 @@ val serialize by tasks.registering(NoDebugJavaExec::class) {
     classpath(rootProject.buildscript.configurations["bootstrapCompilerClasspath"])
     main = "org.jetbrains.kotlin.serialization.builtins.RunKt"
     jvmArgs("-Didea.io.use.nio2=true")
-    args(outDir, *inDirs)
+    args(
+        outDir.relativeTo(projectDir),
+        *inDirs.map { it.relativeTo(projectDir) }.toTypedArray()
+    )
 }
 
 val builtinsJar by task<Jar> {