Log Message:
Update devel/alex to 3.1.7. Fix configure env wrap.

Changes in 3.1.7:
- Add support for %encoding directive (allows to control --latin1
  from inside Alex scripts)
- Make code forward-compatible with in-progress proposals
- Suppress more warnings

Changes in 3.1.6:
- sdist for 3.1.5 was mis-generated, causing it to ask for Happy
  when building.

Changes in 3.1.5:
- Generate less warning-laden code, and suppress other warnings.
- Bug fixes.