For historical reasons (I suppose), the text in the Users Guide
section 5.4 on calling foreign functions from C seems to assume that
you only need C integers (represented by Int). This means it's not clear
what to do if, for example, you need size_t. At the moment I suppose most
people are still using computers which are basically 32 bit throughout, so
at the moment this is something of a non-issue, but in the next few years
I expect this to change, and I think the way GHC is tied to a particular
correspondence C types <-> Haskell types is dangerous. So what I suggest
is that we have a new structure which contains type synonyms corresponding
to the C numeric types (for example CInt, CInt#, CSizeT, CSizeT#, and so
on). Also the manual should be changed to encourage people writing new
code to use CInt rather that Int as the type name for when they want to
call a C function expecting an Int.
