database compactor tool

This is listed in the devchk request list because I see it from devchk, but the
tool is probably fine as standalone.

It would be nice to have a way to identify when former devchk runs have
prompted us to push data which makes arch-specific entries that aren't needed.
Here's one example, an anoymous enum from ftw.h:

/* Flags for fourth argument of `nftw'.*/
#if __LSB_VERSION__ >= 12
    enum {
        FTW_PHYS = 1,
        FTW_MOUNT = 2,
        FTW_CHDIR = 4,
        FTW_DEPTH = 8
    };

#endif

we've ended up with this in devchk, which means there are identical records for
each arch for these values:

#if defined __s390x__
CheckEnum("FTW_PHYS",FTW_PHYS,0,29754)
CheckEnum("FTW_MOUNT",FTW_MOUNT,2,29755)
CheckEnum("FTW_CHDIR",FTW_CHDIR,4,29756)
CheckEnum("FTW_DEPTH",FTW_DEPTH,8,29757)
#elif defined __x86_64__
CheckEnum("FTW_PHYS",FTW_PHYS,0,29754)
CheckEnum("FTW_MOUNT",FTW_MOUNT,2,29755)
CheckEnum("FTW_CHDIR",FTW_CHDIR,4,29756)
CheckEnum("FTW_DEPTH",FTW_DEPTH,8,29757)
#elif defined __s390__ && !defined __s390x__
CheckEnum("FTW_PHYS",FTW_PHYS,0,29754)
CheckEnum("FTW_MOUNT",FTW_MOUNT,2,29755)
CheckEnum("FTW_CHDIR",FTW_CHDIR,4,29756)
CheckEnum("FTW_DEPTH",FTW_DEPTH,8,29757)
#elif defined __powerpc64__
CheckEnum("FTW_PHYS",FTW_PHYS,0,29754)
CheckEnum("FTW_MOUNT",FTW_MOUNT,2,29755)
CheckEnum("FTW_CHDIR",FTW_CHDIR,4,29756)
CheckEnum("FTW_DEPTH",FTW_DEPTH,8,29757)
#elif defined __powerpc__ && !defined __powerpc64__
CheckEnum("FTW_PHYS",FTW_PHYS,0,29754)
CheckEnum("FTW_MOUNT",FTW_MOUNT,2,29755)
CheckEnum("FTW_CHDIR",FTW_CHDIR,4,29756)
CheckEnum("FTW_DEPTH",FTW_DEPTH,8,29757)
#elif defined __ia64__
CheckEnum("FTW_PHYS",FTW_PHYS,0,29754)
CheckEnum("FTW_MOUNT",FTW_MOUNT,2,29755)
CheckEnum("FTW_CHDIR",FTW_CHDIR,4,29756)
CheckEnum("FTW_DEPTH",FTW_DEPTH,8,29757)
#elif defined __i386__
CheckEnum("FTW_PHYS",FTW_PHYS,0,29754)
CheckEnum("FTW_MOUNT",FTW_MOUNT,2,29755)
CheckEnum("FTW_CHDIR",FTW_CHDIR,4,29756)
CheckEnum("FTW_DEPTH",FTW_DEPTH,8,29757)
#else

there is no arch difference here. Seems we should be able to count up cases
where this happens and reduce those down to a single generic entry.