Thanks so much for your help and insight.
Do I have to tell you? I feel stupid about this.
As you probably are aware, I have been doing lots of CHARMM builds lately. And I did this from a BUILD sub-directory in the main CHARMM directory.
1. I used the command ../configure -a CVELO
But, it wasn't correct. Please see Rick's answer, above.
2. After I got an answer from Rick indicating it should be -a CVELOCI, I performed a "make clean" command which left cmake files and directories in the BUILD sub-directory, and then I used ../configure -a CVELOCI
(OK, I did this a few times, after each time that the cvel command wouldn't work; I was in a make clean <--> ../configure DO LOOP)
4. Then I finally did the following: rm -R -f BUILD; mkdir BUILD; cd BUILD; ../configure -a CVELOCI, and cvel commands were now accepted.
So, I think the answer is to use a clean BUILD sub-directory each time one performs a ../configure command.
Again, I apologize any inconvenience this caused.