Fix for --embind-emit-tsd + -sMODULARIZE (emscripten-core#20051)

Fixes: emscripten-core#20012

emcc.py

@@ -1853,7 +1853,11 @@ def phase_linker_setup(options, state, newargs):
     # With this option we don't actually output the program itself only the
     # TS bindings.
     options.output_file = in_temp('a.out.js')
+    # Don't invoke the program's `main` function.
     settings.INVOKE_RUN = False
+    # Ignore -sMODULARIZE which could otherwise effect how we run the module
+    # to generate the bindings.
+    settings.MODULARIZE = False
 
   # options.output_file is the user-specified one, target is what we will generate
   if options.output_file:

test/test_other.py

@@ -2908,8 +2908,11 @@ def test_jspi_add_function(self):
     self.do_runf(test_file('other/test_jspi_add_function.c'), 'done')
 
   def test_embind_tsgen(self):
-    self.run_process([EMCC, test_file('other/embind_tsgen.cpp'), '-o', 'out.html',
-                      '-lembind', '--embind-emit-tsd', 'embind_tsgen.d.ts'])
+    # These extra arguments are not related to TS binding generation but we want to
+    # verify that they do not interfere with it.
+    extra_args = ['-o', 'out.html', '-sMODULARIZE']
+    self.run_process([EMCC, test_file('other/embind_tsgen.cpp'),
+                      '-lembind', '--embind-emit-tsd', 'embind_tsgen.d.ts'] + extra_args)
     actual = read_file('embind_tsgen.d.ts')
     self.assertNotExists('out.html')
     self.assertNotExists('out.js')