feat: Android - backward compatible TurboModule

Author: brianpburns

android/build.gradle

@@ -28,6 +28,10 @@ buildscript {
 
 apply plugin: 'com.android.library'
 
+def isNewArchitectureEnabled() {
+  return project.hasProperty("newArchEnabled") && project.newArchEnabled == "true"
+}
+
 def safeExtGet(prop, fallback) {
   rootProject.ext.has(prop) ? rootProject.ext.get(prop) : fallback
 }
@@ -43,6 +47,17 @@ android {
     versionCode 1
     versionName "1.0"
     buildConfigField 'String', 'INTERCOM_VERSION_NAME', packageVersion
+    buildConfigField("boolean", "IS_NEW_ARCHITECTURE_ENABLED", isNewArchitectureEnabled().toString())
+  }
+
+  sourceSets {
+    main {
+      if (isNewArchitectureEnabled()) {
+        java.srcDirs += ['src/newarch']
+      } else {
+        java.srcDirs += ['src/oldarch']
+      }
+    }
   }
 
   buildTypes {