Fixed unknown pragma warnings for _BitScanReverse.#259

Merged

vitaut merged 2 commits intofmtlib:masterfrom mwinterb:unknown_pragma_bsr

Jan 8, 2016

+61-70

Commits on Jan 6, 2016

Fixed unknown pragma warnings for _BitScanReverse.
mwinterb
committed

Commits on Jan 7, 2016

Don't define the MSVC clz functions unless __builtin_clzll is unavailable.
mwinterb
committed