Rather trying to reinvent this very complex macro, take the easy way
out: Create a real lam_stdint.h which includes stdint.h, inttypes.h or
sys/types.h when possible, and otherwise uses SIZEOF_ macros generated
by configure to fill in the undefined types. A little more work for
cpp if stdint.h is not present.
This commit was SVN r136.
6fa45e4c20