Handle a couple of Windows edge cases better (#1495)

src/event_sources/event_win.cc

@@ -112,6 +112,11 @@ class WindowsEventThread: public Thread {
   void recalculate_handles() {
     int index = 1;
     for (auto resource_event : resource_events_) {
+      if (index >= MAXIMUM_WAIT_OBJECTS) {
+        // Windows only allows 64 handles - we would have to move to a tree to
+        // support more.
+        FATAL("Too many events");
+      }
       if (resource_event->is_event_enabled()) {
         handles_[index] = resource_event->event();
         resources_[index] = resource_event->resource();

src/resources/pipe_win.cc

@@ -511,6 +511,16 @@ static Object* fork_helper(
   if (GetFileType(startup_info.hStdError) == FILE_TYPE_PIPE && !is_inherited(err_object))
     CloseHandle(startup_info.hStdError);
 
+  if (!process_information.hProcess) {
+    // We are running on Wine, and we have started a Linux executable,
+    // which means we can't track when it terminates.  But we already
+    // started the process.  We don't want to define yet another C++-thrown
+    // exception for this marginal case, so we throw one of the standard
+    // exceptions here, but also print a warning on stderr.
+    fprintf(stderr, "Error: Running a Linux executable from Wine is not supported: '%ls'\n", command_line);
+    INVALID_ARGUMENT;
+  }
+
   auto subprocess = new (resource_allocation.keep_result()) SubprocessResource(resource_group, process_information.hProcess);
   proxy->set_external_address(subprocess);