Describe the bug

#include <ctype.h> needs to be added to ext/puma_http11/puma_http11.c. Without this include compilation of Puma will fail due to error:

include the header <ctype.h> or explicitly provide a declaration for 'isspace' 
1 error generated.

This seems to be fixed on 5.0.0.beta1 although it won't help since beta doesn't behave nicely and cannot be used in production.

To Reproduce
Just try to compile puma.

Expected behavior
Succesfully compiled Puma would be expected behaviour :)

Desktop (please complete the following information):
MacOS 15.5.5 and MacOS Big Sur
Puma version 4.3.5