Use SPDX license identifiers to indicate licenses?

[Lassi Kortela]

SPDX license identifiers are becoming something of a de facto standard, 
being used e.g. in Linux kernel source code. Here is the full list of 
them: <https://spdx.org/licenses/>.

Would it be possible to update the ad hoc license identifiers at 
<https://wiki.call-cc.org/chicken-projects/egg-index-5.html> and in .egg 
files to use the SPDX ones? This would make it easier to tell the 
difference between e.g. the various flavors of the BSD license, and 
could help automated tools figure out licensing in the future.

In addition to single license identifiers, SPDX can also do license 
expressions by combining license identifiers using boolean operators.