I've just added SPDX information to SRFI 194.  Would you all please review it to make sure that I haven't missed any copyright attributions?  I didn't include all of you in all the files.  Instead, I used the version control log to see who had contributed to each, and included them.  But it's possible that I missed someone.  In any case, every file is now marked, the MIT license is included, and the repo passes reuse lint.

Here's the change list: