RFR(xxs): 8074547: libjli, get_cpuid() implementation missing for MacOs, breaks libjli.so build in slowdebug

[Thomas Stüfe]

Hi,

please review this tiny change. It fixes a build error on MacOS when
building jdk without optimization.

bug: https://bugs.openjdk.java.net/browse/JDK-8074547
webrev: http://cr.openjdk.java.net/~stuefe/webrevs/8074547/webrev.00/webrev/

Thank you!

..Thomas Stuefe