[PATCH - revised^2] threads 1.71

POD and test tweaks.  (Revise added fixes to SKIPs, and revised^2
fixed a bug introduced in the revised version.  Sorry for the noise.)

• [PATCH - revised^2] threads 1.71 by Jerry D. Hedden
• Re: [PATCH - revised^2] threads 1.71 by Rafael Garcia-Suarez