compile-time version defines

[Heath Kehoe]

I would like to add compile-time #defines with version information.
Something like:

#define INN_VERSION_MAJOR  2
#define INN_VERSION_MINOR  3
#define INN_VERSION_PATCH  1
#define INN_VERSION_EXTRA  "20000824 CVS prerelease"
#define INN_VERSION_STRING "INN 2.3.1 (20000824 CVS prerelease)"

I would have the mkversion script create a .h file with those
defines in it; either <innversion.h> or <inn/version.h>, which
would then be included by libinn.h.

The reason:  so I can maintain just one ovdb.c, and use #if/#else/#endif
in the event that changes to 2.4 require changes to the overview
modules.

-heath