Removing duplicated UNITTEST_POSIX #define from cmdline -D flags
Removing duplicated UNITTEST_POSIX #define from cmdline -D flags

DavidLudwig/unittest-cpp,DavidLudwig/unittest-cpp,grahamreeds/unittest-cpp,unittest-cpp/unittest-cpp,pjohnmeyer/unittest-cpp,jasonhorsburgh/unittest-cpp,jasonhorsburgh/unittest-cpp,grahamreeds/unittest-cpp,unittest-cpp/unittest-cpp,Microsoft/unittest-cpp,pjohnmeyer/unittest-cpp,Microsoft/unittest-cpp,grahamreeds/unittest-cpp,unittest-cpp/unittest-cpp