[8u][gcc6] RFR: 8152132: aarch32: disable -Werror for libsctp

[Alex Kashchenko]

Please review and sponsor the following change to NioLibraries.gmk 
makefile in jdk:

  - issue: https://bugs.openjdk.java.net/browse/JDK-8152132
  - webrev: 
http://cr.openjdk.java.net/~akasko/aarch32/jdk8u/8152132/webrev.00/

libsctp is currently compiled with "-Werror" flag. For GCC6 additional 
flag "-std=gnu++98" is required for hotspot compilation. But due to 
peculiarities of hotspot build flags that option needs to be specified 
using --with-extra-cflags configure option (--with-extra-cxxflags is 
ignored by hotspot). This causes incorrect (for C) "-std" value to be 
applied to all C code in jdk. That causes compiler warnings and libsctp 
breaks compilation because of Werror enabled.

With this jdk change and hotspot changes 8152130 and 8152131 GCC6 
compilation succeeds on Fedora 24 with the following additional 
configure flags:

  --with-extra-cflags="-std=gnu++98 -fno-delete-null-pointer-checks 
-fno-lifetime-dse"
  --with-extra-cxxflags="-std=gnu++98 -fno-delete-null-pointer-checks 
-fno-lifetime-dse"

PS: link to the discussion about the upstream changes related to GCC6 on 
build-dev - 
http://mail.openjdk.java.net/pipermail/build-dev/2016-March/016767.html

-- 
-Alex