[tz] static_assert macro

Hello, The new tzcode uses static_assert() with no message which is a c2x extension. clang does not like that by default (without specifying -std=gnu2x). /home/source/ab/HEAD-llvm/src/lib/libc/time/private.h:1017:52: error: '_Static_assert' with no message is a C2x extension [-Werror,-Wc2x-extensions] || TIME_T_MAX >> (TYPE_BIT(time_t) - 2) == 1); ^ , "" Best, christos