The signal function pointer typedef in
main.c(519) typedef RETSIGTYPE (*bsd_signal_ret_t) ();

will issue:
warning C4113: 'bsd_signal_ret_t' differs in parameter lists from 'sighandler_t'

This is because sighandler_t is defined in MS C-lib signal.h as:
typedef void (__cdecl * sighandler_t)(int);

I don't know if this is different in other C libs but I find it unlikely. GLIBC defines it in signal.h as:
typedef void (*__sighandler_t) (int);

Solution:
main.c(519) typedef RETSIGTYPE (*bsd_signal_ret_t) (int);