[8u] RFR: 8210761: libjsig is being compiled without optimization

[Severin Gehwolf]

Hi,

Could somebody please review this 8u backport? The build system in 8 is
different, especially hotspot makefiles. Note, libjsig.so is part of
the hotspot build. The patch is different in 8 (over 11) due to this
reason. This is a Linux-only change and should be low risk. Thoughts?

Bug: https://bugs.openjdk.java.net/browse/JDK-8210761
webrev: http://cr.openjdk.java.net/~sgehwolf/webrevs/JDK-8210761/jdk8/01/webrev/

Change in JDK 11: http://hg.openjdk.java.net/jdk-updates/jdk11u/rev/e7aa96dc0b1e

Testing: Manual build of slowdebug/fastdebug/release on x86_64.
Fastdebug/release builds receive the -O3 flag, slowdebug not. As
expected.

Thanks,
Severin