clang -O2  -Wall -Wextra -Werror -Wno-error=deprecated -Wno-error=deprecated-declarations signal/pthread_t.c -o signal/pthread_t -D_POSIX_C_SOURCE=202405L  -lm  -lintl
signal/pthread_t.c:2:1: error: unknown type name 'pthread_t'
pthread_t* foo;
^
1 error generated.