cc -pthread  -Wall -Wextra -Werror -Wno-error=deprecated -Wno-error=deprecated-declarations signal/struct-timespec.c -o signal/struct-timespec -D_POSIX_C_SOURCE=202405L  -lm -lpthread  -liconv
signal/struct-timespec.c:2:17: error: tentative definition has type 'struct timespec' that is never completed
    2 | struct timespec foo;
      |                 ^
signal/struct-timespec.c:2:8: note: forward declaration of 'struct timespec'
    2 | struct timespec foo;
      |        ^
1 error generated.