Unable to compile on macOS

Unable to compile on macOS 10.12.6 using Xcode 8.3.2. Error descriptions:
```
strife-ve/strife-ve-src/opl/opl_linux.c:18:10: 'config.h' file not found
strife-ve/strife-ve-src/src/w_file_posix.c:19:10: 'config.h' file not found
```