RFR: 8210761: libjsig is being compiled without optimization

[Severin Gehwolf]

Hi,

Please review this build change which turns on compiler optimization
for libjsig. It doesn't look like there is a good reason to turn off
all opt when libjsig is being compiled. Signal tests[1] which excercise
libjsig in various configs show no regressions for me on Linux x86_64.
Thoughts?

Bug: https://bugs.openjdk.java.net/browse/JDK-8210761
webrev: http://cr.openjdk.java.net/~sgehwolf/webrevs/JDK-8210761/webrev.01/

Testing: Signal tests[1] and jdk submit.

Thanks,
Severin

[1] test/hotspot/jtreg/runtime/signal