x86_64-managarm-gcc -pthread  -Wall -Wextra -Werror -Wno-error=deprecated -Wno-error=deprecated-declarations unistd/_PC_SYNC_IO.c -o unistd/_PC_SYNC_IO -D_POSIX_C_SOURCE=202405L -lm -lpthread -lrt -lintl -liconv
unistd/_PC_SYNC_IO.c:2:17: error: ‘_PC_SYNC_IO’ undeclared here (not in a function)
    2 | int const foo = _PC_SYNC_IO;
      |                 ^~~~~~~~~~~