Implement GetThreadCount for AIX.
Implement GetThreadCount for AIX.

antidotcb/googletest,emaste/googletest,antidotcb/googletest,xnagireddy/googletest,sentient-energy/googletest,ruoka/googletest,google/googletest,ruoka/googletest,xnagireddy/googletest,google/googletest,emaste/googletest,gianricardo/googletest,empiredan/googletest,emaste/googletest,rsalsamendi/googletest,rsalsamendi/googletest,rsalsamendi/googletest,jacklicn/googletest,ruoka/googletest,xnagireddy/googletest,xnagireddy/googletest,google/googletest,sentient-energy/googletest,jlanecox/googletest,fuchsia-mirror/third_party-googletest,jacklicn/googletest,gianricardo/googletest,ruoka/googletest,rsalsamendi/googletest,fuchsia-mirror/third_party-googletest,antidotcb/googletest,jlanecox/googletest,google/googletest,empiredan/googletest,jlanecox/googletest,jlanecox/googletest,jacklicn/googletest,empiredan/googletest,gianricardo/googletest,fuchsia-mirror/third_party-googletest,sentient-energy/googletest,antidotcb/googletest,sentient-energy/googletest,fuchsia-mirror/third_party-googletest,emaste/googletest