ARM GCC: Test failure and narrowing conversion from int to char

[dcorbeil]

Hi :)

There are a few issues that have been introduced by 429cd7b for ARM GCC. Namely narrowing of int to char at the index declaration and the transition_table[guards/actions] test failure. See this example: https://godbolt.org/z/h9fGa7nhq

Is there a workaround or a solution apart from using the commit right before?

Thank you for the great library!

[HazardyKnusperkeks]

The fix is, to use a signed char.