games/adonthell: Fix linking with Python 3.8 and onwards

• Link against libpython via the "--embed" flag for Python 3.8 and onwards.

Excerpt from the log:

main.o: In function `main':
main.cc:(.text+0x1af): undefined reference to `PyImport_AppendInittab'
main.cc:(.text+0x1c2): undefined reference to `Py_DecodeLocale'
main.cc:(.text+0x1cf): undefined reference to `Py_SetProgramName'
main.cc:(.text+0x4e9): undefined reference to `PyModule_GetDict'
[...]

PR: 253815