Fix RLCT_SIGNAL_MASK off-by-one.

src/header/signal/mod.rs

@@ -387,9 +387,13 @@ pub unsafe extern "C" fn sigpending(set: *mut sigset_t) -> c_int {
         .or_minus_one_errno()
 }
 
-const BELOW_SIGRTMIN_MASK: sigset_t = (1 << SIGRTMIN) - 1;
-const STANDARD_SIG_MASK: sigset_t = (1 << 32) - 1;
-const RLCT_SIGNAL_MASK: sigset_t = BELOW_SIGRTMIN_MASK & !STANDARD_SIG_MASK;
+// TODO: Double-check this mask.
+// This prevents the application from blocking the two signals SIGRTMIN - 1 and SIGRTMIN - 2 which
+// are (at least meant to be) used internally for timers and pthread cancellation. On Linux this is
+// 32 and 33 (same as NPTL reserves), whereas this on Redox is 33 and 34 (TODO: could this be
+// changed to 32 and 33 for Redox too, since there's currently no support for "sigqueue" targeting
+// specific threads).
+const RLCT_SIGNAL_MASK: sigset_t = (1 << ((SIGRTMIN - 1) - 1)) | (1 << (SIGRTMIN - 2) - 1);
 
 /// See <https://pubs.opengroup.org/onlinepubs/9799919799/functions/sigprocmask.html>.
 #[unsafe(no_mangle)]