pthread constants and functions for VxWorks

[biabbas]

Changes made are supporting changes for iddm/thread-priority#45

1. Changes name of sched_param in VxWorks so that it matches unix platforms
2. Add pthread constants and functions required for thread-priority.

Requesting for stable nomination.

r? @tgross35

Thank you,
B I Mohammed Abbas

[tgross35]

Thanks for the PR, could you provide links to headers or manpages? Or at least copy+paste the relevant bits of the headers you are testing against to the PR description.

[tgross35]

Do you have links to headers / docs to check against?

Also FYI the commit summary only says "VxWorks"

[biabbas]

Do you have links to headers / docs to check against?

Also FYI the commit summary only says "VxWorks"

I am using original sources to check these changes against. Unfortunately, I can't share them.

[tgross35]

Alright, they match linux so I guess that is straightforward enough. It would be good if we could find somebody who can crosscheck these in the future if sources aren't available.

Thanks for updating the commit message.