RFR: 8144885: agent/src/os/linux/libproc.h needs to support Linux/SPARC builds

[Gerald Thornbrugh]

Hi Everyone,

Please review this small change which fixes a JDK9 Linux/SPARC build problem in "hotspot/agent/src/os/linux/libproc.h”
so the correct “ptrace.h” include file will be used during the build process.

Bug: https://bugs.openjdk.java.net/browse/JDK-8144885 <https://bugs.openjdk.java.net/browse/JDK-8144885>
Webrev: http://cr.openjdk.java.net/~gthornbr/8144885/webrev/ <http://cr.openjdk.java.net/~gthornbr/8144885/webrev/>

Thanks,

Jerry