Merge "zip_writer.cc: update powerof2 and use it unconditionally"

#include "entry_name_utils-inl.h"

#include "zip_archive_common.h"

#if !defined(powerof2)

#define powerof2(x) ((((x)-1) & (x)) == 0)

#endif

#undef powerof2

#define powerof2(x)                                               \

  ({                                                              \

    __typeof__(x) _x = (x);                                       \

    __typeof__(x) _x2;                                            \

    __builtin_add_overflow(_x, -1, &_x2) ? 1 : ((_x2 & _x) == 0); \

  })

/* Zip compression methods we support */

enum {