Main loop is blocked in the libgomp.so library #204

Describe the bug When a new main loop is created and run in the event handler, the main thread will block in libgomp.so.

To Reproduce Steps to reproduce the behavior:

1. Run test
2. Waiting for test results

Expected behavior The main thread is not blocked.

Screenshots

Environment (please complete the following information):

• LCUI version: develop branch
• Build tools: gcc
• OS and version: Ubuntu 18.04.3 LTS

Additional context https://github.com/lc-soft/LCUI/blob/3758e2193930cff9b137eb3c6392ee23ee991472/test/test_mainloop.c#L42-L74