RFR [8u65]: 8072147: Preloading libjsig.dylib causes deadlock when signal() is called

[david buck]

Hi!

This is a request for review of the jdk8 backport of 8072147. As the gcc 
version used to build jdk8 does not directly support thread-local 
storage, I had to rewrite parts of the fix to use the pthreads 
thread-specific data API (pthread_(get/set)specific and friends). Hence 
the need for review, as opposed to simple approval.

Bug: https://bugs.openjdk.java.net/browse/jdk-8072147
Webrev: http://cr.openjdk.java.net/~dbuck/8072147/webrev.jdk8.02/
JDK9 Changeset: 
http://hg.openjdk.java.net/jdk9/hs-rt/hotspot/rev/660fa1b69f63
Review thread for JDK9 fix: 
http://mail.openjdk.java.net/pipermail/hotspot-runtime-dev/2015-June/015282.html

I have tested the fix both manually and via JPRT.

Cheers,
-Buck