--- a/src/hotspot/cpu/x86/globals_x86.hpp	Thu Nov 09 12:43:13 2017 -0800
+++ b/src/hotspot/cpu/x86/globals_x86.hpp	Fri Nov 10 09:16:42 2017 +0100
@@ -84,11 +84,7 @@
 define_pd_global(bool, RewriteBytecodes,     true);
 define_pd_global(bool, RewriteFrequentPairs, true);
 
-#ifdef _ALLBSD_SOURCE
 define_pd_global(bool, UseMembar,            true);
-#else
-define_pd_global(bool, UseMembar,            false);
-#endif
 
 // GC Ergo Flags
 define_pd_global(size_t, CMSYoungGenPerWorker, 64*M);  // default max size of CMS young gen, per GC worker thread