Fix keepRuntimeAlive for pthreads (#22927)

Fixes: #22889

Author: sbc100

src/library.js

@@ -2078,16 +2078,12 @@ addToLibrary({
   // at runtime.
   $keepRuntimeAlive__deps: ['$runtimeKeepaliveCounter'],
   $keepRuntimeAlive: () => noExitRuntime || runtimeKeepaliveCounter > 0,
-#elif !EXIT_RUNTIME
-  // When `noExitRuntime` is not include and EXIT_RUNTIME=0 then we know the
+#elif !EXIT_RUNTIME && !PTHREADS
+  // When `noExitRuntime` is not included and EXIT_RUNTIME=0 then we know the
   // runtime can never exit (i.e. should always be kept alive).
-  // However for pthreads we always default to allowing the runtime to exit
-  // otherwise threads never exit and are not joinable.
-#if PTHREADS
-  $keepRuntimeAlive: () => !ENVIRONMENT_IS_PTHREAD,
-#else
+  // However, since pthreads themselves always need to be able to exit we
+  // have to track `runtimeKeepaliveCounter` in that case.
   $keepRuntimeAlive: () => true,
-#endif
 #else
   $keepRuntimeAlive__deps: ['$runtimeKeepaliveCounter'],
   $keepRuntimeAlive: () => runtimeKeepaliveCounter > 0,

test/test_other.py

@@ -13640,8 +13640,12 @@ def test_pthread_icu(self):
     self.do_other_test('test_pthread_icu.cpp')
 
   @node_pthreads
-  def test_pthread_set_main_loop(self):
-    self.do_other_test('test_pthread_set_main_loop.c')
+  @parameterized({
+    '': ([],),
+    'strict': (['-sSTRICT'],),
+  })
+  def test_pthread_set_main_loop(self, args):
+    self.do_other_test('test_pthread_set_main_loop.c', emcc_args=args)
 
   # unistd tests