[dylink] Share dynamicLibraries array across workers (#19496)

To ensure that the same dynamic libraries are loaded among all
workers, it remains necessary to share the `dynamicLibraries` array,
especially when it is defined outside the module (e.g. in
`MODULARIZE` mode).

Fixes a regression introduced in commit ceb2e28.

src/library_pthread.js

@@ -379,6 +379,7 @@ var LibraryPThread = {
         'wasmOffsetConverter': wasmOffsetConverter,
 #endif
 #if MAIN_MODULE
+        'dynamicLibraries': dynamicLibraries,
         // Share all modules that have been loaded so far.  New workers
         // won't start running threads until these are all loaded.
         'sharedModules': sharedModules,

src/runtime_pthread.js

@@ -129,6 +129,7 @@ if (ENVIRONMENT_IS_PTHREAD) {
         };
 
 #if MAIN_MODULE
+        dynamicLibraries = msgData['dynamicLibraries'];
         sharedModules = msgData['sharedModules'];
 #if RUNTIME_DEBUG
         dbg(`worker: received ${Object.keys(msgData['sharedModules']).length} shared modules: ${Object.keys(msgData.sharedModules)}`);

test/test_core.py

@@ -9412,13 +9412,17 @@ def test_Module_dynamicLibraries(self, args):
     self.emcc_args += args
     self.emcc_args += ['--pre-js', 'pre.js']
     self.emcc_args += ['--js-library', 'lib.js']
-    # This test is for setting dynamicLibraries at runtime so we don't
+    # This test is for setting dynamicLibraries at runtime, so we don't
     # want emscripten loading `liblib.so` automatically (which it would
-    # do without this setting.
+    # do without this setting)
     self.set_setting('NO_AUTOLOAD_DYLIBS')
 
     create_file('pre.js', '''
-      Module['dynamicLibraries'] = ['liblib.so'];
+      if (typeof ENVIRONMENT_IS_PTHREAD == 'undefined' || !ENVIRONMENT_IS_PTHREAD) {
+        // Load liblib.so on the main thread, this would be equivalent to
+        // defining it outside the module (e.g. in MODULARIZE mode).
+        Module['dynamicLibraries'] = ['liblib.so'];
+      }
     ''')
 
     create_file('lib.js', '''