libgraphicsenv: get linker symbols from real header

Test: build, flash and boot
Change-Id: I181430f0f0caef6ee5590c2ed2bf3e7e90e4ed0d
diff --git a/libs/graphicsenv/Android.bp b/libs/graphicsenv/Android.bp
index 56521bf..f11cf62 100644
--- a/libs/graphicsenv/Android.bp
+++ b/libs/graphicsenv/Android.bp
@@ -32,5 +32,9 @@
         "libutils",
     ],
 
+    header_libs: [
+        "libnativeloader-dummy-headers",
+    ],
+
     export_include_dirs: ["include"],
 }