unknown constant name 'COLOR_DARKGRAY' in 'GetConstantNumber'
**Describe the bug**
Getting following error when trying to run exe file compiled from python script:
`pyxel error: unknown constant name 'COLOR_DARKGRAY' in 'GetConstantNumber'`

**To Reproduce**
Steps to reproduce the behavior:
1. Compile python to exe with [auto-py-to-exe](https://pypi.org/project/auto-py-to-exe/)
2. Run compiled exe

**Desktop (please complete the following information):**
 - OS: Windows 10 x64
 - Python 3.8
 - Pyxel 1.4.1
