cc -pthread   -Wall -Wextra -Werror -Wno-error=deprecated -Wno-error=deprecated-declarations stdalign/alignas.c -o stdalign/alignas -D_POSIX_C_SOURCE=202405L -lm -lpthread -lrt  -lgdbm_compat -lcrypt -latomic
stdalign/alignas.c:3:2: error: #error "alignas is not defined"
    3 | #error "alignas is not defined"
      |  ^~~~~