diff --git a/libsystem/Android.bp b/libsystem/Android.bp
index 4d076d5..846a585 100644
--- a/libsystem/Android.bp
+++ b/libsystem/Android.bp
@@ -1,4 +1,15 @@
 cc_library_headers {
     name: "libsystem_headers",
+    vendor_available: true,
+    host_supported: true,
     export_include_dirs: ["include"],
+
+    target: {
+        linux_bionic: {
+            enabled: true,
+        },
+        windows: {
+            enabled: true,
+        },
+    }
 }
diff --git a/libsystem/include/system/window-deprecated.h b/libsystem/include/system/window-deprecated.h
index d1ef1e7..2ccfd66 100644
--- a/libsystem/include/system/window-deprecated.h
+++ b/libsystem/include/system/window-deprecated.h
@@ -32,6 +32,8 @@
  **************************************************************************************************
  **************************************************************************************************/
 
+#pragma once
+
 #include <cutils/native_handle.h>
 #include <errno.h>
 #include <limits.h>
@@ -326,6 +328,12 @@
      * if it is safe (i.e. no crash will occur) to call any method on it.
      */
     NATIVE_WINDOW_IS_VALID = 17,
+
+    /*
+     * Returns 1 if NATIVE_WINDOW_GET_FRAME_TIMESTAMPS will return display
+     * present info, 0 if it won't.
+     */
+    NATIVE_WINDOW_FRAME_TIMESTAMPS_SUPPORTS_PRESENT = 18,
 };
 
 /* Valid operations for the (*perform)() hook.
@@ -445,6 +453,14 @@
  */
 static const int64_t NATIVE_WINDOW_TIMESTAMP_AUTO = (-9223372036854775807LL-1);
 
+/* parameter for NATIVE_WINDOW_GET_FRAME_TIMESTAMPS
+ *
+ * Special timestamp value to indicate the timestamps aren't yet known or
+ * that they are invalid.
+ */
+static const int64_t NATIVE_WINDOW_TIMESTAMP_PENDING = -2;
+static const int64_t NATIVE_WINDOW_TIMESTAMP_INVALID = -1;
+
 struct ANativeWindow
 {
 #ifdef __cplusplus