cython code: add some int types to get rid of unspecific python add / subtract operations

they somehow pull in some floating point error code that led to a undefined
symbol FPE_... when using the borgbackup wheel on some non-ubuntu/debian linux
platform.

borg/chunker.pyx

@@ -20,7 +20,7 @@ cdef extern from "_chunker.c":
 cdef class Chunker:
     cdef _Chunker *chunker
 
-    def __cinit__(self, seed, chunk_min_exp, chunk_max_exp, hash_mask_bits, hash_window_size):
+    def __cinit__(self, int seed, int chunk_min_exp, int chunk_max_exp, int hash_mask_bits, int hash_window_size):
         min_size = 1 << chunk_min_exp
         max_size = 1 << chunk_max_exp
         hash_mask = (1 << hash_mask_bits) - 1

borg/crypto.pyx

@@ -52,7 +52,7 @@ bytes_to_long = lambda x, offset=0: _long.unpack_from(x, offset)[0]
 long_to_bytes = lambda x: _long.pack(x)
 
 
-def num_aes_blocks(length):
+def num_aes_blocks(int length):
     """Return the number of AES blocks required to encrypt/decrypt *length* bytes of data.
        Note: this is only correct for modes without padding, like AES-CTR.
     """