Fix typo in macro
Xcode gives the following warning:
./common/helpers/pow.h:1:9: warning: 'ENTANGLE_POW_H' is used as a header guard here, followed by #define of a different macro [-Wheader-guard]
Xcode gives the following warning:
./common/helpers/pow.h:1:9: warning: 'ENTANGLE_POW_H' is used as a header guard here, followed by #define of a different macro [-Wheader-guard]