Use ssize_t instead of int where necessary

Author: 1st1

uvloop/handles/process.pyx

@@ -204,7 +204,7 @@ cdef class UVProcess(UVHandle):
     cdef char** __to_cstring_array(self, list arr):
         cdef:
             int i
-            int arr_len = len(arr)
+            ssize_t arr_len = len(arr)
             bytes el
 
             char **ret

uvloop/loop.pyx

@@ -2312,7 +2312,7 @@ cdef class Loop:
         """
         cdef:
             Handle handle
-            int n
+            ssize_t n
 
         if self._debug and sock.gettimeout() != 0:
             raise ValueError("the socket must be non-blocking")

uvloop/sslproto.pyx

@@ -23,7 +23,7 @@ cdef:
     str _SHUTDOWN = "SHUTDOWN"
 
 
-cdef int READ_MAX_SIZE = 256 * 1024
+cdef ssize_t READ_MAX_SIZE = 256 * 1024
 
 
 @cython.no_gc_clear