add size_t to FFI usable types, print better error message in 'lookupCType'
add size_t to FFI usable types, print better error message in 'lookupCType'

darcs-hash:20070530001322-1a7c6-cb50c3d881f627ff2206f56acb7122ad27f40338

jimcrayne/jhc,jimcrayne/jhc,jimcrayne/jhc,jimcrayne/jhc