cmake HAVE_BSR64 examples

HDFGroup/hdf5 config/cmake/LIBAEC/CMakeLists.txt :37 

check_c_source_compiles (
    "int main(void){unsigned long foo; unsigned __int64 bar=1LL;
return _BitScanReverse64(&foo, bar);}"
    HAVE_BSR64)

InsightSoftwareConsortium/ITK Modules/ThirdParty/HDF5/src/itkhdf5/config/cmake/LIBAEC/CMakeLists.txt :37 

check_c_source_compiles (
    "int main(void){unsigned long foo; unsigned __int64 bar=1LL;
return _BitScanReverse64(&foo, bar);}"
    HAVE_BSR64)