cc -pthread   -Wall -Wextra -Werror -Wno-error=deprecated -Wno-error=deprecated-declarations poll/sigset_t.c -o poll/sigset_t -D_POSIX_C_SOURCE=202405L -lm -lpthread -lrt  -lgdbm_compat -lcrypt -latomic
poll/sigset_t.c:2:1: error: unknown type name ‘sigset_t’
    2 | sigset_t* foo;
      | ^~~~~~~~