osx clang blows up if pthreads flag at link time 2

Signed-off-by: Andy Green <andy.green@linaro.org>
diff --git a/CMakeLists.txt b/CMakeLists.txt
index e019d37..bd9430f 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -481,7 +481,7 @@
                 set(VISIBILITY_FLAG -fvisibility=hidden)
     endif()
     if (UNIX)
-               set(CMAKE_C_FLAGS "-Wall -Werror ${VISIBILITY_FLAG} ${CMAKE_C_FLAGS} -pthread" )
+               set(CMAKE_C_FLAGS "-Wall -Werror ${VISIBILITY_FLAG} ${CMAKE_C_FLAGS}" )
     else(UNIX)
                set(CMAKE_C_FLAGS "-Wall ${VISIBILITY_FLAG} ${CMAKE_C_FLAGS}" )
     endif(UNIX)