The SurvivorRatio flag used to be a platform dependent flag. It was changed to a platform independent flag with this change from October 2009:

http://hg.openjdk.java.net/jdk9/hs/hotspot/rev/473cce303f13

/src/share/vm/runtime/globals.hpp

- product_pd(intx, SurvivorRatio, \
+ product(intx, SurvivorRatio, 8, \

However, when the BSD port was integrated in 2011 the platform specific definition for BSD came in along with the port:

http://hg.openjdk.java.net/jdk9/hs/hotspot/rev/f08d439fab8c

/src/os_cpu/bsd_x86/vm/globals_bsd_x86.hpp

+define_pd_global(intx, SurvivorRatio, 8);

Both definitions are using the same default value, so there should be no need to have this platform dependent.