Use existing macros for atomic.wait return values. NFC (#26475)

Author: sbc100

system/include/emscripten/atomic.h

@@ -183,7 +183,10 @@ _EM_INLINE void emscripten_atomic_fence(void) {
 
 #define ATOMICS_WAIT_RESULT_T int
 
-// Numbering dictated by https://github.com/WebAssembly/threads/blob/master/proposals/threads/Overview.md#wait
+// Numbering dictated by https://github.com/WebAssembly/threads/blob/master/proposals/threads/Overview.md#wait:
+//   0 => "ok", woken by another agent.
+//   1 => "not-equal", loaded value != expected value
+//   2 => "timed-out", the timeout expired
 #define ATOMICS_WAIT_OK 0
 #define ATOMICS_WAIT_NOT_EQUAL 1
 #define ATOMICS_WAIT_TIMED_OUT 2

system/lib/pthread/emscripten_futex_wait.c

@@ -136,7 +136,7 @@ int emscripten_futex_wait(volatile void *addr, uint32_t val, double max_wait_ms)
   }
 
   // -1 (or any negative number) means wait indefinitely.
-  int64_t max_wait_ns = -1;
+  int64_t max_wait_ns = ATOMICS_WAIT_DURATION_INFINITE;
   if (max_wait_ms != INFINITY) {
     max_wait_ns = (int64_t)(max_wait_ms*1000*1000);
   }
@@ -166,16 +166,12 @@ int emscripten_futex_wait(volatile void *addr, uint32_t val, double max_wait_ms)
 done:
   emscripten_conditional_set_current_thread_status(EM_THREAD_STATUS_WAITFUTEX, EM_THREAD_STATUS_RUNNING);
 
-  // memory.atomic.wait32 returns:
-  //   0 => "ok", woken by another agent.
-  //   1 => "not-equal", loaded value != expected value
-  //   2 => "timed-out", the timeout expired
-  if (ret == 1) {
+  if (ret == ATOMICS_WAIT_NOT_EQUAL) {
     return -EWOULDBLOCK;
   }
-  if (ret == 2) {
+  if (ret == ATOMICS_WAIT_TIMED_OUT) {
     return -ETIMEDOUT;
   }
-  assert(ret == 0);
+  assert(ret == ATOMICS_WAIT_OK);
   return 0;
 }