Use __SCCSID for SCCS IDs in libkvm sources.

[jhb]

Summary

Rather than using #ifdef's around a static char array, use the
existing helper macro from <sys/cdefs.h> for SCCS IDs. To
preserve existing behavior, add -DNO__SCCSID to CFLAGS to not
include SCCS IDs in the built library by default.

Test Plan

• Built a libkvm and compared 'readelf -p .comment' before and after.
• Also accidentally got the CFLAGS wrong the first try which showed the SCCS IDs in .comment.

[brooks]

LGTM. I'm not sure the blank line between FBSDID and SCCSID is useful, but don't care much one way or another.

[jhb]

Yeah, I actually meant to post a comment asking about the blank line. I would be fine with collapsing it now that the ID isn't surrounded by N layers of #ifdef.

[rgrimes]

In D15459#326241, @jhb wrote:

Yeah, I actually meant to post a comment asking about the blank line. I would be fine with collapsing it now that the ID isn't surrounded by N layers of #ifdef.

I would like to see the blank line collapsed.

Other than I like the decluttering effect this patch has.

[• karels]

Looks good to me. I could go either way on the blank line.

[dab]

I'd prefer the blank line be dropped, but I don't feel strongly about it.

[jhb]

• Remove extra blank lines.