fix incorrect definition of RUSAGE_CHILDREN in sys/resource.h

the kernel ABI value for RUSAGE_CHILDREN is -1, not 1. the latter is
actually interpreted as RUSAGE_THREAD, to obtain values for just the
calling thread and not the whole process.

include/sys/resource.h

@@ -68,7 +68,7 @@ int prlimit(pid_t, int, const struct rlimit *, struct rlimit *);
 #define PRIO_USER    2
 
 #define RUSAGE_SELF     0
-#define RUSAGE_CHILDREN 1
+#define RUSAGE_CHILDREN (-1)
 
 #define RLIM_INFINITY (~0ULL)
 #define RLIM_SAVED_CUR RLIM_INFINITY