Fix composite build against shared

Gradle executes buildSrc logic in a separate classloader.
Thus we need to build sources of the composite shared
in buildSrc and include them in runtime dependencies of
the buildSrc:plugin project.

buildSrc/plugins/build.gradle

@@ -43,13 +43,9 @@ dependencies {
     // Support composite build against kotlin-native-shared.
     // Gradle cannot substitute a dependency in buildSrc by an included build.
     // See: https://github.com/gradle/gradle/issues/3768.
-    // Thus we have to compile sources of the included shared once more
-    // and depend on them during buildSrc compilation.
-    // We don't add this dependency in the runtime scope because build scripts
-    // already depend on kotlin-native-shared and this dependency is correctly
-    // substituted by the included build.
-    if (hasProperty("sharedProjectPath")) {
-        compileOnly project(':shared')
+    // Thus we have to compile sources of the included shared once more to use it in buildSrc.
+    if (project.hasProperty("sharedProjectPath")) {
+        compile project(':shared')
     } else {
         // If there is no composite build against shared, add a dependency on a published jar.
         compile "org.jetbrains.kotlin:kotlin-native-shared:$sharedVersion"

buildSrc/shared/build.gradle.kts

@@ -20,7 +20,7 @@ plugins {
 
 val sharedProject = file(property("sharedProjectPath")!!).resolve("src")
 
-kotlin.sourceSets["main"].kotlin.srcDirs.add(sharedProject)
+kotlin.sourceSets["main"].kotlin.srcDirs(sharedProject)
 
 dependencies {
     implementation(kotlin("stdlib"))