Let libmemunreachable use bionic_libc_platform_headers.

Bug: 135772972
Change-Id: I2702abce849a46292dc467f9083f3b6816bfc5e6
diff --git a/libc/Android.bp b/libc/Android.bp
index 8284174..243371b 100644
--- a/libc/Android.bp
+++ b/libc/Android.bp
@@ -1812,8 +1812,10 @@
         "//external/perfetto:__subpackages__",
         "//external/scudo:__subpackages__",
         "//system/core/debuggerd:__subpackages__",
+        "//system/memory/libmemunreachable:__subpackages__",
     ],
     host_supported: true,
+    vendor_available: true,
     recovery_available: true,
     native_bridge_supported: true,
     export_include_dirs: [