Comment 3 for bug 1640317

Hm, maybe that is a red-herring?

Because it tries in a few places and eventually finds the right place (pthread)

-- Looking for pthread.h
-- Looking for pthread.h - found
-- Looking for pthread_create
-- Looking for pthread_create - not found
-- Looking for pthread_create in pthreads
-- Looking for pthread_create in pthreads - not found
-- Looking for pthread_create in pthread
-- Looking for pthread_create in pthread - found

The actual error seems to be with gmock?

CMake Error at /usr/src/googletest/googletest/cmake/internal_utils.cmake:149 (add_library):
  add_library cannot create target "gmock" because another target with the
  same name already exists. The existing target is a static library created
  in source directory "/usr/src/googletest/googlemock". See documentation
  for policy CMP0002 for more details.
Call Stack (most recent call first):
  /usr/src/googletest/googletest/cmake/internal_utils.cmake:172 (cxx_library_with_type)
  /usr/src/gmock/CMakeLists.txt:84 (cxx_library)

CMake Error at /usr/src/googletest/googletest/cmake/internal_utils.cmake:149 (add_library):
  add_library cannot create target "gmock_main" because another target with
  the same name already exists. The existing target is a static library
  created in source directory "/usr/src/googletest/googlemock". See
  documentation for policy CMP0002 for more details.
Call Stack (most recent call first):
  /usr/src/googletest/googletest/cmake/internal_utils.cmake:172 (cxx_library_with_type)
  /usr/src/gmock/CMakeLists.txt:89 (cxx_library)