Fixed a minor cmake problem, occuring when DYNAMIC_CORE=ON and CMAKE_C_FLAGS was empty
Fixed a minor cmake problem, occuring when DYNAMIC_CORE=ON and CMAKE_C_FLAGS was empty

xianyi/OpenBLAS,xianyi/OpenBLAS,xianyi/OpenBLAS,xianyi/OpenBLAS,xianyi/OpenBLAS,xianyi/OpenBLAS,xianyi/OpenBLAS,xianyi/OpenBLAS