Fix conflict when BMI2 is enabled and --single-amalgamation-file
Fix conflict when BMI2 is enabled and --single-amalgamation-file

Not sure why this wasn't causing an error in the MSVC CI builds.

webmaster128/botan,webmaster128/botan,webmaster128/botan,randombit/botan,webmaster128/botan,randombit/botan,randombit/botan,randombit/botan,randombit/botan,webmaster128/botan