--- old/make/autoconf/platform.m4	2020-05-07 15:01:12.168796125 -0700
+++ new/make/autoconf/platform.m4	2020-05-07 15:01:11.796788977 -0700
@@ -526,6 +526,9 @@
   PLATFORM_SET_MODULE_TARGET_OS_VALUES
   PLATFORM_SET_RELEASE_FILE_OS_VALUES
   PLATFORM_SETUP_LEGACY_VARS
+
+  # Deprecated in JDK 15
+  UTIL_DEPRECATED_ARG_ENABLE(deprecated-ports)
 ])
 
 AC_DEFUN_ONCE([PLATFORM_SETUP_OPENJDK_BUILD_OS_VERSION],