#40 Use proper datatypes for 'long long'

[Enrico Scholz]

xmlrpc-c uses 'long long' at some places (e.g. in printf
statements with PRId64) under the assumption that it has a
width of exactly 64 bits.

On 64 bit machines 'long long' has a width of 128 bit and
will cause overhead both in memory and cpu usage there. As
'long long' is used only to handle <i8> datatypes, the patch
uses a plain 64 integer type there.

It is arguable whether 'int_least64_t' (and 'int_least32_t')
would be a better choice for 'int64_t' (and 'int32_t'), but
for now, the patch uses datatypes with exact widths.

[Enrico Scholz]

replaces 'long long' by a proper datatype