RFR(M): 8187045: [linux] Not all libraries in the VM are linked with -z,noexecstack

[Lindenmaier, Goetz]

Hi,

I found that not all libraries are linked with -z,noexecstack.
This lead to errors with our linuxppc64 build.  The linker omitted
the flag altogether, which is interpreted as a lib with execstack.

This change contains a small test that scans all libraries in the tested VM
to have the noexecstack flag set. It utilizes the elf parser in the VM for this.
Further -z,noexecstack is now passed to all libraries.

Please review this change. I please need a sponsor.
http://cr.openjdk.java.net/~goetz/wr17/8187045-execstackLink/webrev.01/
http://cr.openjdk.java.net/~goetz/wr17/8187045-execstackLink/webrev.01-hs/

Best regards,
  Goetz.