As a side-effect of this change, we also resolve a a problem with
signed file version numbers, so that instead of version 2147483647
wrapping to -2147483648 we can go as far as 4294967296 before we
have issues. Various sprintf() formats get changed from %d to %u.
The DOS version code is left behind as int versions.
As a prerequisite for cleaning up some other include issues, all the
include files in inc/ should have an include guard. All the xxxdefs.h
were created with them, but most older files were not.
