Allow using libandroid_headers_private on host builds

This is needed to create a host implementation of RenderThread.

Bug: 322360037
Test: build libandroid_runtime on host
Change-Id: I23f78155e0d2c511451e3e249537b83ca06f411a
diff --git a/Android.bp b/Android.bp
index 8c4dfbb..2520a71 100644
--- a/Android.bp
+++ b/Android.bp
@@ -105,7 +105,13 @@
 
 cc_library_headers {
     name: "libandroid_headers_private",
+    host_supported: true,
     export_include_dirs: ["include/private"],
+    target: {
+        windows: {
+            enabled: true,
+        },
+    },
 }
 
 filegroup {